I cleaned all 5 less than a year ago, but I didn't apply any grease. It has been cranking a little more slowly lately, so while working on other projects, I pulled the L battery and found this.
While working on the terminals, I put the battery on the charger so it wouldn't damage the alternator or starter.
After removing the bolt & any spacers, peel the rubber off the edge of the terminal plate, then pick and brush all the corrosion off. Likewise, clean the battery terminals. Coat everything with ELECTRICAL grease (not dielectric, thermal, or chassis) before reassembly. The bolts are invariably UNDERsized (making them more-likely to strip out the threads in the Lead battery terminal), so replacing them with 3/8" stainless threaded rod & stainless nuts will dramatically increase clamping force. Aftermarket bolts are also available, which are easier to install than threaded rod.
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