This topic needs expanding upon!
Dumpster diving is the act of finding goods in a dumpster. The act of "diving" is essentially going through the trash of a business to seek out the products that would otherwise go to waste.
Scrap metals, cardboard and other recyclable materials are frequently sought after treasure of those who dumpster dive. Increasingly desired as a commodity of divers is edible healthy food and as prosaic as it sounds, a lot of food goes to waste when a business cannot sell it due to "quality control," expiration dates and/or faulty packaging.
San Francisco has a very long and extensive history of recycling and dumpster-diving, from the famous and philanthropic "Diggers" and "Food Not Bombs" to the infamous and downright demonic Jim Jones' "People's Temple" and "The Manson Family."
A vast majority of San Francisco businesses have gone to great lengths to prevent the gleaning of goods from their dumpsters. Most common methods of deterrence include the "bar & lock" dumpster, fenced and locked enclosures, and massive sized trash compacters.
Today (2009) city wide waste diversion is more prevalent than ever, making dumpster diving even more challenging. Read all the "how-to" manuals on dumpster diving like: Art & Science of Dumpster Diving, Empire of Scrounge, Dumpster Diving: The Advanced Course and, you will still find that dumpstering in the City can be quite daunting. How to find free commodities, even when it's someones trash, is often hard learned and, the sharing of such knowledge is not always in the best interest of those in the know. However, there are those who believe in the socio-economic benefit of proliferating dumpster diving and are willing to assist those who are interested.
Common consensus is to check out the dumpsters at Rainbow Grocery (Folsom St. @ 14th St.) around 9:15pm on Wednesdays or Sundays. While enjoying the frequently prevalent array of seasonal organic produce available (some even prior to reaching the dumpster itself,) be sure to engage in conversation with any number of regulars who frequent this Freegan foraging urban oasis . As of October 2009, the dumpsters are put out on Folsom St. near 14th St. around 9:15pm every night EXCEPT Saturday and it is not uncommon for 5 to 10 people to be very close behind. The current crew of regulars is a politically, ethnically, gender, and age diverse group. Many of whom are un/under-employed artists, sculptors, poets, writers, clinical chemists, actors, artisan carpenters and, although some may well have a crusty veneer, they are solid and kind hearted. Recently, they held a curbside Freegan potluck with Sprouted Four Bean Curry, Fresh Green Bean Balsamic Salad, Build Your Own Sandwich / Salad Bar, Almost Vegan Pear Berry Pies (top crust was OMG brushed with egg white) and a Vegan Glazed Apple Bread Pudding. If you decide to check out the Rainbow dumpster scene, please respect those undergoing food scarcity as well as respecting the need to keep the sidewalk clean and accessible. It is important that any and all boxes, unclaimed goods etc. are placed back in the appropriate dumpsters and the lids are gently/quietly closed before leaving.
Another good dumpster can be found outside Trader Joe's in the Richmond at 3 Masonic Avenue. At one point in time, there were also great bread finds at the bakery outlet located at 16th and Folsom. The produce terminal surrounding the intersection of Jerrold and Selby streets in the Bayview frequently overflows with fresh fruits and vegetables, simply ride your bike in a big loop around it and stop at each of the 15-20 dumpsters and check it out! Another good choice is the bagel joint at Gary and 15th. You will find fresh bagels which only defect is not being perfect looking. Several nights a week you will also be delighted to find cookies and other pastries.