title_body: How do I keep slime from collecting in my drip tray?
upvoted_answer: If what you're seeing is mold or algae you may want to add a few table spoons of salt to the drip pan.
  
  I'm guessing that your slime is probably a fungus of some kind, rather than an algae. It has found a rather nice living arrangement for a fungi. Plenty of warm water and decomposing coffee, with very little light.
  
  Salt should in most cases prevent fungal growth, this may sound odd but it will dehydrate the cells even when they're immersed in water, sort of a "water, water everywhere but not a drop to drink".
  
  If you would rather get high tech with it, you could try a UV light, similar to the ones used in AC systems. The harsh UV rays will kill most molds and prevent them from colonizing.