I was tipped to this process by a guy at a Gould Battery plant.
What to do. Boil water and add some Baking soda to it.
Disconnect the terminals and pour the hot soda water over the crud.
It will dissolve and can be cleaned off. You must get it all cleaned well.
Next take a small tube of Silicone RTV calking and go around the base of
the lead post where they come out of the plastic top. Wet your finger
and smear the calking down to get a good seal and then let it harden for
an hour or two.
In the meanwhile, use some anti-corrosion paste on the lead terminals
and cable clamps before reconnecting them.
Different companies make this stuff.
If you will do this you won't have problems with corrosion.
As for these things....Red & Green Felt corrosion prevent devices.
Save your money. You could buy the anti-corrosion Jelly for what these cost and be better off.
Why ?
The plastic top of the battery will eventually shrink back from the lead terminal post. Then the vapors will spew up through the gap and under the cable clamps and start the corrosion process.
The RTV will bond with the plastic top and lead post and expand and contract with temperature change like a rubber gasket, thus keeping those vapors in the battery so your terminals won't corrode.
This is one of the greatest TIPS I've ever gotten for working on my own cars. I've never had any warranty issues with this either. No one has ever asked. But if they did, I'd just tell them it's corrosion preventative.
