I was clearing out stuff from my attic, came across a few boxes of cassettes. One in particular I thought may be worth a listen, so I popped it on. It was a board tape of a somewhat famous Scottish soul/funk band from a 'coming home' concert in Glasgow 1986. I recorded it from the main outs of the Soundcraft 32/8/2 which was the main board of my rental company at the time. This was the first time I had mixed this particular band.
This tape had been in the box for 20 years, had crossed the Atlantic, and was in pretty bad shape - it broke twice when I was playing it.
I carefully repaired the cassette and recorded it into Sonar.
I did a bunch of stuff to it with various mastering tools, and finally came out with something pretty surprising, considering the source quality. Bear in mind, this is a live board mix. There's a bad ground hum, which came from the record deck being slaved from the outs of another cassette deck which was recording a tape for the band's road manager. There's also all the other artefacts of a 20 year old cassette recording - hiss, no top end, lack of dynamic range, etc etc. For comparison, here's two sample WMA partials -