JS 2 BLE connection Failing

I'm not sure how well the casing/pins will response to attempts to clean up the old polish first with polish cleaner stuff...

Thanks for checking - yes, the pins should be ok but the case will melt with Acetone which is normally in nail varnish remover. Maybe your stuff will be better - but you could try first on a small patch under where a strap attaches so if it messes up something you'll never see it :)

Things like IPA (Isopropyl alcohol) will be totally fine, but won't soften the paint.

I think as long as you've cleaned the area with detergent to get any oils off, applying paint on the old paint would be ok if it really has worn away.