I would love to see the coin. Porous coins are a real problem with no simple answers, or, in reality, no answers at all. The only thing would be to fill the pores with some substance, kind of like Bondo-ing over a repair on a car. Powdered copper might do it, but would come out easily. Don't let Thad know I said this, but you could put on a layer of VerdiChem.
In your opinion yes you are right. I personally buy junk coins just to restore. And coins I have bought for $1 or 2 with a little tender love and care, olive oil, and a few months..and I was able to resell them as hole fillers for much much more then I spent. My best find to date was a dirty correded half cent...few months later enough detail came thru and it turned out to be an 1802 over 0 with the reverse of 1800. Granted its in piss poor condition..but its still a high dollar key date. Coins shouldn't be cleaned. But when a coin has no value as is...its not hurting anything. And there are a lot of people who need temerary hole fillers. The saying goes a coin is only worth what someone is willing to pay for it. Lol. I must admit when I read that ketchup was used in cleaning....I was shocked...I don't recommend using ketch on copper or bronze coins....ever.