LOL, all I have is old gear. I use soft toothbrush to keep items like the "kiss" looking good.
I also use a bit of gun wax or even a bit of oil. For tougher cleaning I use Simichrome or brass cleaner. I always start with a soak in Dawn soap, ultra sound then go from there for more stubborn ones. Oh Renaissance wax is good for all from wood to all my metals to protect
Acetone is really good to remove stubborn grime and you can actually drop your whole switch into some pure acetone for about 5 to 10 minutes to keep things clean in between full breakdown. GUS mods themselves told me about the acetone and said that short soaks wont hurt the insulators but do remove any orings.
In my collection I only have 2 sx minis, 1 Prov classic, 1 Kainos box. The rest are all old tubes that I LOVE cause no matter how grimy they get, good simple mechs can always be brought back to like new. They just work. I use mostly 18500 or 350 since I vape mostly at home. When I do go out and about, its my little SX mini Mclass "brick" that goes out with me.