Often, when there is lots of green and/or white cauliflower type corrosion next to the battery posts, it indicates that the battery clamp hardware was overtightened, and the seal around the post itself, broken. Then when charging, instead of charging gasses escaping from the cell caps, they exit right though the bases of the posts and acceleration of corrosion is inevitable with that sulfuric acid mist that escapes with the hydrogen and oxygen gasses.
Do Not get Baking soda inside the cells. With the recessed caps on many batteries this is not easy to accomplish.
Peanut butter? I've never heard of that one. I would avoid such products with high prejudice on battery terminals just for the rodent factor as it seems some vehicles use peanut butter infused wires, when presented to the right rodent.
A good thick high temp grease is good for protection after cleaning of ALL corrosion, and this means removing the connections and cleaning thoroughly, not just cleaning what can be seen while everything is still connected.
One other thing to note is to take a picture of the connections before removal, or mark themn (+) and (-) as SOOOOO many reports exist online of somebody either cleaning corrosion and or replacing their battery hooking it up incorrectly and causing possible extensive damage to electrical components when reversing the polarity on reconnection.
The felt washers I have seen are dry and need to be impregnated with grease.
If the cauliflower corrosion has wicked under the wire insulation it can cause issues too, and remain invisible. I have personally seen such horrid corrosion creep up the battery cables and cause a no start and or No charge condition. Even when the insulation was stripped off and the wires wire brushed shiny, the resistance at the connection was so high, the heating so bad under starting or charging currents, that cable replacement was necessary and the solution. I am not quite sure how electrons could decide to not flow through copper surrounded by corrosion, later cleaned off, only that the copper simply had developed such high resistance where the corrosion was, that the cable was too compromised to pass any significant current, and the only solution was replacement.
I did once cut off a problem battery lug and a few inches of cable and crimped on a new lug onto the same cable with only a slight improvement, and replacement was again the solution, and the effort and new cable lug crimped on, a waste of time and money.
If there are remaining issues with starting or charging after a battery swap and or terminal cleaning, consider the cables themselves to be compromised and replacement necessary. Appearance alone of battery cables is not definitive as to whether they are adequate or compromised.
And a clean tight protected connection is a good investment in reliability and starting and recharging performance.
Do make sure to check the main battery to engine and battery to firewall grounds where they connect to to engine and firewall. These are notorious for causing current bottlenecks and bizarre electrical issues. Once again outward physical appearance is not indicative of their condition. Remove, file to a silvery finish, and retighten.
