Vallejo hates alcohol. I forgot to flush my AB super good to remove any remnants of IPA. A week later I shot Vallejo and it gummed up immediately and I had to strip it all down. Now if I have to flush out IPA, after the AB has been reassembled, I run through a ¼ AB cup of Medea Airbrush Cleaner, ¼ AB cup of VMA and two AB cups of water. So far so good. I've had my Vallejo Metals for over 4 years and still using them. Just used them on my two P-51s