Short story: Cat Crap. Longer story: Was having the usual early-season fogging problems on track (like at Beaverun in April, 37F and wet). A friend was going to Iron Pony. I told him to pick me up some sort of antifog and I'd pay him for it. He comes back and throws "Cat Crap" on my desk. WTF, I give him $8. Didn't use it all season because the rest of the track days were warmer. Went to the drag strip last week, after dark was having major fogging problems. I'd keep my visor open until the other lane prestaged, then close it on my thumb. If the other lane took more than a second or two to stage, I'd be blind until about 660. Dealt with this most of the night, then at one point I picked up my helmet off my truck and it was covered with dew on the outside of the visor. I figured at this point I was totally screwed, then I remembered the Cat Crap was in my gear bag. I hastily, in the cold damp dark, hit the visor inside and out with Glass Plus and paper towel, a smearing of Cat Crap, and buffed with a terry cloth of questionable cleanliness. Breathed on the visor, no fog. Looked through it, no haze or streaking under the lights. Wore it closed the rest of the night, not the slightest hint of fog or dew. Awesome.