I have seen this before with kitchen utensils and the so called "Soft Grips" and suspected that the soft rubber coating on the Fox NX alarm cases was to blame. So I tried to rub it off with the usual kitchen cleaners but to no avail.
A quick call to Fox Customer Services didn't help. Yes, it was a known problem. Yes there had been a product recall several years ago (missed that one even though I registered the alarms). They could replace the cases at £28 an alarm but they had no NX cases left. So the suggestion was try some isopropyl alcohol and if that didn't work then bad luck. Or words to that effect. Not what I expect from the Fox boys to be honest but that's another subject altogether. Oh, and isopropyl alcohol doesn't work.
Luckily I am also a modeller. Plastic kits, model railways, Warhammer, all that jazz. In my travels I have come across a wonderful paintstripper from Phoenix Precision designed for removing paint from plastic kits without melting them - DON'T try Nitromoors or similar which will melt your cases. It's called PS18 Superstrip.
To use it, take the alarms as far apart as you want - I didn't bother but did take the batteries out. Give the cases a liberal coat of the Superstrip and gently agitate with a stiff brush. Over a period of 20 minutes or so the thin rubber coating on the cases will wrinkle up and can be gently brushed off. Clean the cases in water when all the wrinkled rubber coating has come off and give them a good dry. You may need a pin or similar to get the last bits out from around the control knobs. Try not to get the Superstrip into the speaker enclosure or around the roller mechanism.
My alarms are good as new now, with no sticky coating. At about 30 minutes per alarm, this was a good few hours spent pre-season sorting out my gear. I do love the NX alarms, so was happy to do this.
