Gunk BTC6-12PK Battery Terminal Cleaner - 5 oz., (Case of 12)

The cleaner is soda based and neutralizes the battery acid. Be careful where you spray it since it can kill the battery. The cleaning solution washes of with water.

I have used this but can not say how good it works yet but for the price it was well worth the try.

Didn't by it from Amazon; local stores and other sites sell it for less. Nevertheless, the stuff gets rid of corrosion wery well. I've had a huge growth on the negative terminal that'd spread to the cable (a technician had somehow broken the battery top around the negative post and acid leaked out) voltage drop in the clamp went up and starting was affected. Scraping alone didn't do a thing. BTC4 came and saved the day. It still took quite a bit of repeated spraying, scraping and rinsing, but in the end I've got the clamp and post shining.Following the instructions on the can is important. It is not enough to just spray and wipe; some salts are convertet into other salts that water dissolves (at least, this is how it looks). The reaction isn't instant, so be patient and give it the requested 5 minutes. Then scrape, or brush, or both; then rinse and repeat.