back to the topic:

tires are pretty forgiving and can take lots and lots of punctures before the strength is seriously compromised. For larger holes, I'll take a strip or two of cotton hbar tape and put in inside the tire for extra protection; plastic coke-bottle type platic also works well as a tire patch, but you need to be careful about the edges. All of my skidding tires are ones that I've either pulled of clients' bikes and patched, or pulled out of shop dumpsters and patched.