I don't think stainless bits will enjoy being anodised... I dunked a split ring that was supposed to be Ti but I suspect it was stainless... lot of fizzing (hydrogen), sparks (not compatible with hydrogen) and a faintly yellow stained split ring...
There is no acid involved with anodizing Titanium--it can be done with a simple electrolyte solution, such as TSP.
Note that I am not that I'm advocating sticking a SPY in any solution, however.
Tri-sodium phosphate is a strong alkali. A 1% TSP solution has a pH of 12 -- drain cleaner may be 100x stronger, but TSP is still a reactive chemical. Electrolytes + Electricity + Imperfect waterproofing = Dead electronics.
All I'm saying is it would suck to break something as expensive as a SPY.
Just $0.02. Depending on the active solvents(or not), any rubbber, dirt, oil or grease could render the tank of solution unuseable. We used to chromate alluminum, prior to painting, and every piece needed to be grease, dirt, and rubber free.
I will always advocate complete disassembly of flashlights before a chemical process, regardless of the material used to build it. Whether it's a $1000 Spy, or a $69 Four Sevens, they should be disassembled cleaned and prepped for the coating/coloring process.