how can I clean/repair my EJ DE89 gold?

There's a fair bit of build up on the thread and the knurling on the bottom of the handle. Tried the obvious toothbrush and detergent method but to no avail, is there something a bit more suitable that won't strip the plating?

Scrubbing bubbles.

Looks like early stage Zamak rot. There is no cure for that unfortunately.

Hi,
If the plating is gone then it's gone!

The obvious fix for that is to replate!

If that is not an option then you might want to try a FINE brass bristle brush or #0000 steel wool!

Then polish with FLITZ!

They don't replate Zamak.

+1 on the #0000 steel wool, I also use MAAS polish, I roll it around a Qtip to get it into tight spots then use a clean Qtip to remove it and the tarnish.