Just buy new tubes. Most cheap tubes are made in Taiwan, and almost every brand I have used in the last 12 years or so (cheap tubes here) have had KENDA marked on them...

$5-8 each, even locally. Get a proper size spare, too. You can get tubes for $5 online, and if you buy 3 at a time, even with shipping its probably less than buying local, if you can wait. Qtubes have served me and many others well.

If you have deep section rims, make sure to buy a longer valve stem. They usually cost the same!