it probably does need to be cleaned, but from the small amount of knowledge I have is that theres "wet" and "dry" tape formats, sony uses wet, panasonic uses dry, not sure about other manufacturers. From what i've been told its not good at all on your heads to be switching back and forth. Also, I don't use the same camera to import to my mac, I have a canon XL1 thats only used to film, and a crappy consumer camera that I do the transfers with. I dont know how good of a camera you have, but if you've been switching tape brands, filming and transferring with the same camera, the heads are probably pretty worn and it may just be time for a new camera.