Saving Some War Cents

The attempt to fix or clean those is good for experimentation but the end results will still be sort of junk status. And although might end up being worth 2 cents or more, still an interesting experiment. AND if you add up all the time and money spent doing this, each coin could end up costing way more than the end results.
WD-40 is only a brand name. If you check out most stores you would find a large variety of penetrating oils. Some might work better on those coins but again, lots of time and money invested.

Did you look at the picture? Before he started they were worth basically 1 cent each so he can't hurt them. They won't be worth any more but they may be more attractive to a non-collector.