Is it possible to have a cassette tape edited, so that you can hear it crystal clear?

I have a home made cassette tape, which I can barely understand the conversation on.Is it possible to have a cassette tape edited, so that you can hear it crystal clear?
There are professional systems that can clean them up a bit, but they are very expensive and you never get ';crystal clear';.





You are generally stuck with the quality of the original recording.