I should have answered both your questions in one post. On cleaning, it is best to follow individual mfg's suggestions on when to clean, most go by weight. Weigh the suppressor new unfired, document, fire away and weigh it again periodically. .4oz of gunk sticks in my head as enough to warrant a clean job.I do not own a suppressor, I would love to some day, if they will pass al law not requiring an ATF permit and 200.00 tax.. I do have a question for those that run them, how often do you need to clean them? What happens if you fail to clean them, does it cause a failure that will require a new one? Also, to own multiple suppressors, so you need an ATF approval and 200.00 stamp per suppressor owned?