I’ve let mine sit dirty for years. Never had a problem to my knowledge. If I remember to clean and oil before I put them up the great, if I don’t, I don’t worry about it. They are stored in a vault that is climate controlled. I think most people worry about this way too much. I don’t clean until accuracy drops off or I have other problems. Now I did have a 6CM that developed a carbon ring after probably 700 rds suppressed and it got to where it wouldn’t chamber most rounds and was popping primers. Obviously time to clean. Still accurate as hell but still trying to work out why it’s still popping primers and still has a hard bolt lift even after s thorough cleaning.