Technically speaking, no, we cannot delete 'dead' coins in our wallet like it is a social media account that we no longer use unless it is ERC20 tokens, maybe? Kidding aside, as what have been said on thr earlier posts of other users you can send your coins into unknown addresses but their would be a gas money which would be some kind of a hassle. I suggest keeping them as a remembrance. You are not the only one being in such situation. I also have many dead coins, and I doubt others don't especially those who are here for years already. Most of the dead coins I have, are from bounty projects way back 2017 before the huge decline occurred. I have no choice but to keep them with quite of a hope that those coins will have a value someday, if there would be a miracle which would lift the market in general. Selling those coins would be a waste of time at this moment. You would rathet get a 'loss' than earning profit from doing so.