How to repair damaged heatshrink tube

Sometimes I get audio or power equipment with damaged wiring or wiring with a damaged heat shrink tube around a wire or a socket.
The obvious solution is to put in new wiring.

However sometimes this is very impractical or even impossible. Is there any product that can be used to repair a damaged heat shrink tube?
For large coax cables I have used self-vulcanizing rubber tape in the past, so perhaps something like this exists for thin wires?

Regards, Gerrit