I read about "caffenol" developer online and had to try it. Caffenol is a developer made with water, Folger's Crystals, and Arm & Hammer Washing Soda (not baking soda). I shot a roll of Ilford SFX200, probably underexposing it, and developed it for 30 min. in caffenol. Here's a shot from the roll. I'm going to try again soon; it was pretty neat. Apparently, if you add vitamin c to the mixture, it gives a speed/contrast boost and reduces the stain to the base.