I. Basic knowledge/preparations
When diving, the most important thing to have is discretion, both in the sense of being discreet and of using some judgment. As a diver, you are presented with a lot of opportunities to cause injury to yourself. Heeding some of the following suggestions will help you avoid many of them, but again, the final word is your discretion.
As far as physical things you can equip yourself with, the primary tool to have is a light of some sort. The inside of a dumpster is generally very dark, even if you choose to dive in the daytime. And when it comes down to it, dumpsters are used for things people have no use for. This could be expired meat, a router, books, or cat litter. You'll want to know which one you're grabbing. A headlight will keep your hands free to lift or move objects, but a flashlight will certainly do the job. I used a MiniMagLite similar to the one here for the longest time. Only recently have I gone to a headlight, now using the Petzl Zipka.
Decent clothing is a must when diving, as well. Dumpsters often have broken glass, strange chemicals and rust in high quantities. Sturdy shoes and clothes you don't mind getting dirty or torn allow you to take your mind off some of the environmental charms. In addition, some divers choose to use gloves and/or some sort of prodding stick to aid in actual trash handling. Keep in mind the kind of environment you're going to be in. If you're diving construction trash, it's likely there will be a few nails here and there. The local video or grocery store, however, probably won't be throwing out too many dangerous items.
Now that you're ready to dive, you might want to consider taking along a friend with you. Companions are great for several reasons. They have different needs, so you might be able to make more use of the things you find. They also look after you (and vice versa) so as to avoid problems. Plus, friends just make things a lot more enjoyable. Diving can be a very peaceful and exciting experience. Sharing it with your friends is even better. And even if you don't find anything, you still get to walk and talk with your buddies.
An important thing to keep in mind when diving is other people. This means other divers, store managers, passersby, garbagemen, and authority figures. The garbagemen are people whom you probably won't interact with too often, but they are very important, since they regularly remove the garbage. Keeping their schedule in mind will ensure a bountiful dumpster for you.
Keeping the managers, passersby and authority figures in mind will ensure that that bountiful dumpster remains unlocked or doesn't turn in to a compactor. This means you probably want to dive when there aren't so many people around, such as at night after business hours, or early in the morning. The overall idea is to keep confrontation to a minimum, and have whatever confrontation that occurs be a positive and/or respectful one. You aren't out there to cause trouble, or assert some right to access their trash, because the trash is technically their property still. Although you are unlikely to be prosecuted for dumpster diving, the store manager does have the upper hand, and it would be wise to respect that. A good policy is to leave a dumpster cleaner than you found it. This is respectful both to the store managers and to other divers.
I personally have had very few problems with people. Often you hear of divers having very positive relationships with policemen as the result of occasionally finding post-robbery purses discarded in dumpsters. As well, they are witness to a lot of suspicious activity, since they are out at very early or late hours in a low-lit alleyway. YMMV.
Above I referenced locked dumpsters and compactors. These are amongst various deterrents to divers. Other popular ones are razorwire/barbed wire fences around a dumpster, surveillance cameras, or bleach put in to discarded food products (something I find rather offensive). These measures generally come about when the divers in the area are seen as a problem, or when a store throws out valuable equipment, such as an electronics store. The presence of these varies by region, as compactors are almost only at grocery stores and electronics stores in Atlanta, whereas in Worcester, almost every single dumpster is locked. Your reaction to these deterrents is, again, at your discretion. You will have to assess your safety and the situation for yourself. But keep in mind that these are all in place as a sign that divers are not welcome. Think twice about anything you do to circumvent these measures, and think thrice before climbing inside of a compactor. They can crush you very easily.
II. Types of trash
The seasoned diver will find his head turning at a pile of trash on the side of the road much as if it were a pretty woman or a nice car. Residential trash is among the most varied, and often pretty useful too. Furniture, appliances, lamps, books, clothing are all common items. Of course, people don't tend to buy good things just to throw them out again, so it's typical that these items are not functioning to their fullest potential. This often either does not matter, or can be fixed with some creativity or a soldering iron in a few minutes. The
other interesting part of residential trash is the weird stuff that people have in their closets that they finally decided to throw out. Among other things, I recall once finding an artificial scrotum with cancerated testicles inside, used to
illustrate what testicular cancer feels like. It feels lumpy.
Food trash is such an excellent and plentiful source of dumpster diving glee that it is worthy of its own category. However, eating something from a dumpster is not something many would readily take part in, and the obvious reason behind this is that there is a lot of really gross food out there. You're not homeless. You're not out there to settle and take what you can get. If you have doubts about it, then don't take it. It's already trash anyways. The saying is: "use some sense, and use your senses." If it smells a little funky or has just a little too
much squish to it, then let it be. With that out of the way though, there is still an abundance of food which can be consumed safely.
In the previous paragraph on diving deterrents, I mentioned razorwire fencing. In fact, the only dumpster I know of with razorwire around it is the dumpster behind the local Krispy Kreme doughnutery. And yes, razorwire is the same thing used to keep prisoners from escaping. That is how plentiful the doughnuts are. Places like Krispy Kreme and bakeries are such easy targets because an essential quality of the storebought baked good is freshness and hotness. Thus, day-old baked goods are trashed or given to homeless shelters. We have the option to stock up once a week from our local bakery, but often we have so many bagels, baguettes, focaccia, cinnamon buns, coffee rolls, and bread loaves from previous dives that it isn't necessary to stock up but once a month or every three weeks. Grocery stores which don't employ the use of compactors also sometimes have a selection of fruits or vegetables. You can usually find some good candy behind drug stores, frequently in large quantities. About the worst place to dive for food is an actual restaurant. There is really very little there except lettuce scraps, a really bad smell, and strange liquids.
The final trash type is that of offices and normal businesses. This is as varied as the residential, but doesn't tend to be as consistent, since businesses have significantly more papering and such to throw away. However, just because a business makes a certain product doesn't guarantee that you'll find that product in the dumpster. After a while you learn which businesses throw out what. I have a steady supply of zipties and cat 5 ethernet cable from the local satellite installation place. I use the zipties, and Georgia Tech students seem more than willing to buy the spools for $35 (or about 10-12c/foot). A gold bracelet, 16x2 character LCD screens, credit card numbers, recorded phone interviews, a gas station (there are gas pumps, signs, and gas flow computers sitting out behind
a local business park) - these are all items I have found. I have not made use or recorded any of the credit card numbers, but it goes to show just what a range there is. I obviously tended towards more computer-type businesses, but just about every business has its own outside, accessible dumpster. There's bound to be something to please. About the only place I can think of where there is not bound to be something to please is at a hospital. I highly recommend that you never dive at a hospital.
III. Seasonal considerations
The most obvious of the seasonal considerations is the weather. Diving after it has rained is not pleasant and will totally soak anything in an open-top dumpster. The other seasonal aspects are with regard to the diving season - when things tend to be thrown out in high quantity. The end of the month is big for apartment moveouts and evictions. Mid-December and, more importantly, mid-May are fantastic dates to score some couches, TVs, computers, clothing, and food from the local college's residence halls, with many students moving out and few with the desire to fly back home with all of their acquireds. Another excellent thing to pay attention to is major holidays. Last year we found 93 lbs of chocolate on a post-Easter dive, thrown out on the basis that Easter was over.
The less predictable seasonal elements are people/businesses moving locations, or stores going out of business. There is also the technological element, such as when the video stores made room for DVDs by throwing out many, many VHS videos and video games. There's not a really good way to tell when these are coming about aside from looking at other signs, such as the prevalence of DVDs in our society, or perhaps the physical signs that say "GOING OUT OF BUSINESS."
That should have you well on your way to diving like a pro. But, if you should desire a bit more instruction or advice, or are just looking for other divers, alt.dumpster is full of nice people to chat or trade with. Please be aware that when discussing diving on the internet, it is common practice to obfuscate business names, as this tends to increase the longevity of diving hotspots. A place like "Kinko's" might become "Stinko's," or "that copy place with two Ks." Also be aware that some take diving very seriously and are not completely open to sharing their diving spots with just anyone. No worries though, there's enough trash to go around.