Most of them are artificially created. Stay far, far away unless you EXACTLY what natual toning looks like.
they are all proofs and I paid about 20 dollars for all 5. could they still fetch more if I put them in a 5 coin case and try to resell them
I also have a set of UNC 1988 D coins-half quarter dime nickel and penny- the Dime Quarter and Half are already getting gold toned and the half is starting to get a blue and pink ring around it. I actually lost this set about 6-7 years ago in my house and just found yesterday in my closet in a box I noticed they had started to get different colors on them how much could they be worth?
Silver naturally tones with exposure to elements, like hydrogen sulfide which is present in any material. Some coins tone naturally, others the toning is artificially caused by someone. Naturally toned coins have a very small premium, and the premium can depend on how much eye appeal the toning adds to the coin. I've paid no more than $5 over FMV for a naturally toned coin.
If you sell them on eBay you probably could. However, I don't think you'll get much or you might lose some cash over shipping, eBay fees and PayPal.
like whats already been said, NT coins will sometimes have a small premium. it really depends on the looks. most Ebay toners, will look crazy, because they mess with the pictures to bring out more colors. this is my newest NT toned coin. actually the pictures do it no justice. its fully toned, but does not show in the pictures. but this will give you a good idea on a NT lincoln.(also, the black spot on the obverse is actually blue, some reason it turned up black).
Those are articially toned, probabley from using a heat source. The dead give away, if those pics are from a silver proof set, the pennies in those sets are copper and zinc, no silver and wouldn't tone like that Lincoln is. Same with the nickel.
I bought a rainbow toned coin but I didn't really by it for that I won the auction because I needed the coin for my book. I didn't really take the toning in consideration when I bid. https://www.ebay.com/itm/395116793322