Hello!
Maybe a stupid question, but I have to ask anyway:
Has anyone colored a light body with a spray can before? How good or bad will it be? Will the color come off immediately when putting the light into a pocket? Wonder how long it would last.
Yeah, I should simply try it with a cheap light, but happy to hear any opinions on that : )
I don’t know about flashlights, but when people use spray paint on cars, it always looks terrible. 
Not a good idea. Try powder coating.
Well, reason I am asking about simple spray cans is because it´s… simple ^^
Poweder coating sounds like a bigger task.
Also the lights don’t work so good anymore
Naw it’s simple you just bring it to the powder coating shop and pick it up later
Of course you can spray it, and it won’t affect how the light works unless you spray the threads, just mask them off. The problem will be wear, if you just use regular auto spray without several layers of laquer it won’t be very hard wearing (and even if you do it will still chip easy as it’s not baked like a car would be), of course you could use spray enamel or plasticote which would be stronger. As for powder coating, well it won’t be cheap unless you know someone who does it. Not a big job but most places will charge you a standard fee, no matter how small the item is. Better off just buying one already coloured really, unless you specifically want to do that light.
Yes, did some googeling and you are right (about everything).
Well, I guess I won´t get a (matte) grey light then.
I did “recoloring” differently; I wrapped my Olight i3T EOS with heat shrink. When I was buying it’s only available in black. I wrapped it with yellow heat shrink to improve its conspicuity , it worked great IMO
After about one week I then changed it to red. I prefer red 
well, you can get that grey finish easy! just take the anodising off with drain cleaner or alike, it’s gone in seconds and goes matte grey!
Don’t leave too long, it takes about 1 minute, then give it a good wash off in soapy water. If you really wanted you could then spray it with matte laquer - only because the dry aluminium will grab grease and dirt easy, but it adds to the patina I think. If it’s not matte enough you can rough it up with fine wire wool too.
Tear it apart and bake it . Strip it
Or buy a grey light 
That depends on the job. I have two trucks painted in spray paint that most people, even car people swear are professionally painted.
They were done with the same prep as auto paint; fully cleaned, sanded, cleaned, degreased, primed, scuffed, and then painted… even after a decade and a little fade I still get comments on such good factory paint, most think its factory single stage auto paint or a good single stage re-spray.
I also have a Jetbeam BC10 that I sprayed the body of about a decade ago in a hammer finish copper paint(no primer this time) that is still 90% copper color, only the high points of the knurling has worn down to black. It has the same or maybe less pocket/use wear as the body on other lights the same age.
Use a good quality paint, sand the light lightly, and actually follow all instructions on the can to the letter, and it works well IMNSHO.
@AK-Adventurist
Good to know! 