The only really reliable way to clean the ARP CTS sliders is to desolder them, take them apart and clean them. I'm sure I must show the procedure in one of my videos. I would take the two tabs off the ends, then the conductive and resistive tracks pop out. I'd wash the housing to clean it, polish the conductive track with a dremel with wire brush attachment, gently clean the resistive track, wash the shaft and polish the wipers with the dremel, lubricate with fader grease, and then re-assemble. Huge pain in the butt, but these things are black holes for dirt and nastiness and spraying stuff inside doesn't get them clean.
Ultimately I found it wasn't worth the time to do it, and I started stocking new replacements (visit my site and grab a set if you decide to replace them). I'm also going to be putting out an LED slider kit for the Axxe shortly.