I had some of my CO2 yeast sludge boil over into my tank and was able to fix it overnight.
I remembered from my high school Biology class several years ago that hydrogen peroxide kills yeast from an experiment we did in class. I did a bit of research and found that up to 1ml of 3% hydrogen peroxide (what comes in most consumer bottles of the stuff) can be put in a tank per 30 liters and be safe for your fish. I put 2.5ml of the solution in my 20 gallon using one of those kid medicine syringes and set up an air stone with pretty hefty air flow and the yeast was completely gone in the morning. I turned off all the lights in the tank as light breaks down hydrogen peroxide faster.
To save a bit of cash, I took out the airline tubing to the diffuser in the tank and purged it with around 200ml of hydrogen peroxide as well. Just fill up that same syringe, stick the end into the airline, and inject that puppy. Repeat until you stop seeing tiny bubbles coming out, then do it a few more times.
I also added a bubble counter with vitamin C in its water. The idea is that the anti fungal properties of ascorbic acid will kill any yeast hitch hiking into the tank without damaging the fish.
Note that if you do this, you will have to recycle your tank. I've got a large bottle of SeaChem Stablize that has all the bacteria you need. When I used it to set up my tank from new, it cycled the tank in just little over a week and has been golden since. 0 ammonia, nitrates, and nitrites with the plants (and I'm fairly non religious about water changes).
My fish and plant are all doing great so far. I have chocolate gouramis, rainbow fish, rummy nose tetras, a rainbow shark, an algae eater, and a handful of shrimp. The plants are indica, ludwiga, sword grass, and a couple grasses and needle-ee plants I can't recall. The chocolate gouramis and rummynoses were a bit stressed, but most of that was due to the massive current I induced with the air stone (I had a 50 gallon air pump with all the outputs running into one line into a 24 inch bubble bar).