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I would try cleaning it out before you do anything. I've been running an AC50 for years and it is quiet as can be. I just clean everything out real good with a pipe cleaner.
I've cleaned it out really good a few times with a q tip but it won't shut up! I saw an article about using Vaseline but I'm not sure if it's harmful to the tank.
I think the q-tips would just jam more stuff into the motor housing. I would recommend picking up a pack of pipe cleaners from the dollar store the next time you are out. I found a bag at my local dollar store that had all different sizes (and colors) of pipe cleaners in it.