Bacteria: The Friendly Germs
Every cleaning and sanitation step you do serves the purpose of suppression of spoilage bacteria and wild yeast. Some brewers take a step outside all the chemicals and efforts to pursue a chance to add the funk to their beer. However, this isn't the wild and wooly world of lambic brewing they roam through. Both Wyeast and White Labs provide cultures of Brettanomyces strains, Lactobacillus, and Pediococcus.
Brettanomyces bring earthy, spicy, pineapple fruity flavors to a beer. Brett does better with a starter to build up their slow growing populations. With sufficient time and starter size, you can pitch a beer with nothing but Brett and attempt a full “wild” fermentation. It will take longer and be less active, but you get a remarkably aromatic character.
Brettanomyces save their biggest aroma and flavor show for their performances in secondary as backup singers. Flamboyantly wild earthy flavors spring forth along with a touch of acidity. To achieve this character, make a large, decanted starter and add a shot of food: sugar syrup, boiled DME, fresh starter wort, and so on, then sit back and wait. After a month, a slightly greasy white film (a “pellicle”) will form and the Brett's real work begins. An additional six to nine months later your reward will be an off-kilter beer that surprises people.
Regarding equipment, keep track of what gear touches the wildlife. If you can, use separate fermenters, racking canes, tubing, and kegs for these beers. It will simplify your life. If that's not to be the case, super sanitize everything thoroughly unless you want the Brett to develop as a part of your house profile, like some Belgian breweries.