Looking at the M and the O mostly, but this looks doubled to me, any thoughts would be great. also found a 44 war nickel. also, if a coin is silver, will cleaning it silver cleaner destroy the value?
When looking for double dies its important to know what to look for so here are some links that will greatly increase your understanding of what constitutes a real double die....
Read these two articles completely and you will be able to attribute them. Once you get the hang of it they will jump out at you like a red flag its not all that hard if you are given the correct information, good luck.....
Yes, any cleaner (even soap and water) can destroy a coin's collectible value. You certainly don't want to do it to any coins that are collectable (the exception is coins that are -literally- dug out of the ground or perhaps coins that have toned so black that the date/mintmark cannot be made out at all), but when it comes to a war nickel, assuming it isn't a rare variety, cleaning it won't hurt its value since its just worth silver scrap anyways.
However, it might be very hard to get your nickel looking good because of the alloy that the Mint used which contains manganese which makes the coins turn a green-ish hue with little time and exposure to air.