as for how to remove taint.
I'm curious about what method you have in mind, although I have to say that you are missing one important fact. The fact that there is no such thing as "taint", it is just a fake concept created by those who wanted to regulate centralized services like exchanges and then put pressure on them to regain their full surveillance control.
In other words it doesn't matter what we do to "remove taint", they can just call something else like the block reward tainted!