[The Newell]

Corrosion is 'oxidation' and the goal here is to keep the 'oxygen' away from the lead posts and cable terminal ends...there are dissimilar metal components involved - steel bolts, zink plating, etc...which add to the 'corrosion' component on a battery top, helped along by the sulfuric acid fumes from the battery's electrolyte.

Those felt pads are a great way to get some 'protection' for the undersides of the cable terminal connection. Keep the pads 'lubed' with some WD40 type stuff every few months to keep the pads from drying out.

A protective coating can then be slathered or sprayed on the top and sides of the connections to help keep the 'oxygen' away... commercial sprays work, if they remain 'flexible' over time...anti-seize compound is good, and usually has finely ground lead in it, is rather heavy and won't 'flow' away...I also use Petroleum jelly in some cases where the battery connections won't attract dirt and dust, as on a marine application...the old military 'cosmoline' is really good stuff if you can find it, but is nasty to work with as it gets on your tools, fingers, etc, and is hard to get rid of!

RECAP: Keep the terminals coated with something to keep the air away! and as Steve put it use some grease.