Who is this?. And what do you think? should I clean more every coin or beter leave to stay all coin like it is when you get it from the ground? Do you wear glove when you touching old coin or not? If sweat can damage old coin or not?
It's Emperor Valerian and I would leave the coin alone, looks thin and brittle. Hold it however you want, so long as your hands don't have BBQ sauce or Cheeto dust on them.
I don't think there is a single answer. It would be necessary to look at each coin and decide what is best to be done. This coin looks a bit overcleaned or too harshly cleaned. Almost all ancients will require at least some cleaning but not all will require the same type or amount of 'processing'. Valerian is from the time of the worst billon alloy and some of his coins simply will not look great no matter what you do. Earlier coins had a little more silver and look better. Coins later than his had less silver but look better because the copper looks healthier without that amount of silver. Bad things happen when you bury billon in soil for so many centuries. We see a lot of later Valerian coins that look like yours and that is not good.
