The name brand manufacturers will honor the warranty if you clean the vape as well as you can. It's not even an issue for some models. Most whip type vapes don't collect residue-it's in the whip, and you don't need to return that. The cleaning info is on their site or in the instructions/manual. Some tell you flat out that if they receive a vape that hasn't been cleaned they'll send it right back. I've never heard a single instance of a cleaned vape being turned away. They usually have a disclaimer -'not sold for vaporizing illegal substances', but they know what the primary use is. If they used the 'cannabis residue excuse' (after the owner did a good cleaning job) to avoid honoring a warranty, word would get around and their business would suffer. I had a problem with my herbalAire last year (probably caused by my sloppy cleaning job). That model does collect some residue, and although I cleaned it, I couldn't remove all traces by any means. They said to ship it back and as soon as I let them know I shipped it, they shipped me a brand new one-the whole kit.