[Martin Bush]

I'm. Thanks to advice on another thread I now have a better dial on its way.

It's not perfect but hopefully clearer than the current one.

So my question is how best to clean it? I presume the main part will be fine with soap and water. However in my experience the ridged rim always has mystery dirt almost welded in one or two of the valleys between ridges as well as decades of ingrained dirt.

What should I use to get at these without risking damaging the perspex either by scratching or discolouration? Would white spirit be OK for instance?