I checked out the ingredients in Contax. Heptane(50%), cylclohexane(10%), propane(20%), ethyl alcohol(10%), isopropyl alcohol(10%). Based on this, you can make a cheap, effective substitute using butane and 99% isopropyl alcohol, in a 3:1 or 4:1 ratio. Cost would be less than $2(for a hell of a lot more than you get from Contax), from your local CVS, RiteAid, etc. Also looked into the other two products. Neither of which contains anything most people would easily be able to purchase. However, a can of one of the tv tuner, contact, etc. cleaners that tv repairmen use would be equivalent. I knew they used to be about $12, for a large can. Not sure how much they go for now, but would be a fraction of the cost of Kontac or ProGold.