I've been given a CB400/4 that is partially restored & asked to finish the job but i've never seen a loom this filthy. It looks almost like the loom has been covered in chain oil, then dipped in a well used rabbit hutch then dragged across Bridlington beach

I've been cleaning it using a range of brushes/cleaner soaked rags & a compressor but i'm getting nowhere fast.
I don't want to charge the owner a fortune in labour costs either.
But he does want to keep as much of the 'originality' of the bike too, so stripping & re-wrapping is not an option. And to be honest, other than the amount of crap on it & the odd DIY connector, the loom is in good condition.
Any ideas?
I was going to put it through the dish washer but Mrs Howie won't let me
