I have tried a few marking methods, but the one that stuck (literally) was orange Brother p-touch labels (as flags) with my name on them on all cables. My logo is orange & black, so bands know anything orange is mine. I haven't counted cables in a few years as they have stopped walking. I also tell bands the only cable they need is a guitar cable. My mic stands have my branded bumper sticker marking them.
We do something similar... one thing we did to prevent mics from disappearing - and I don't believe most are "stolen" but inadvertently put away by some bands "groupie" or "helper" - is we changed out all the "silver" shure screens for black ones.