I guess this is a product review of sorts.
A few months back, I found a bottle of Slime at the bottom of a box of bike junk in my closet. I have no idea where or when I got it. Slime is that green stuff you put in your tubes to seal punctures. What the heck, I thought, it can't hurt, and I put it in the tubes of my commuter bike (cheap Kenda 700x35 tires and tubes, if that's relevant).
The other day I returned from work and locked my bike up outside my apartment building. A couple of hours later I came out and saw that the tire was flat. It must have been punctured shortly before my arrival, and the air leaked out by the time I came back out of the building. OK, no problem. I brought the wheel inside (hey, it's much nicer to work in air conditioning in this weather), got out my patch kid, removed the tire and tube, and found the puncture. It was easy -- there was green Slime leaking out of the hole. I cleaned up the Slime, went through the usual patching drill, and put it all back together. Easy enough.
But the Slime didn't seal the puncture. And it was a very small puncture. It's possible that it may have slowed down the escaping air, since I did make it home without noticing that I had a flat. I thought that I should give Slime the benefit of the doubt, and I examined the tube closely to see if there were any other punctures that had been sealed by the Slime, but there weren't.
So there's my experience with Slime. I wouldn't bother to use it again. Also, it smells really bad after being in the tube for a few months. I mean really bad.