I have to clean up some tags that have junk characters at the end (e.g. Merle Haggard堀) using Convert Codepage. However, after converting to English (1252), it still leaves ??? as replacement characters, so I still have to do cleanup manually. Is there a way to automatically remove them after converting?
Yes, that would be the case if the tags were not read properly by other programs and consequently written with ISO encoding.
There is no way to guess which the original characters might have been.