Hi all During the weekned I was taking some pics with my Canon Elan 7 in a very dusty evironment. Every now and then I gave the lens a blow and brush to keep it clean, but after a while I saw some spots in the viewfinder. The front of the lens was clean so I took it off, cleaned the back and the mirror but the affensive particles could still be seen. Thing is, my prism is really dirty and I don't know how to clean it... I tried the blowing brush but the specs were too firmly attached. Should I try harder with the brush? Should I use some lens cleaning solution? Lens cleaning paper? ???? Thanks!