First of all, this is my first post here so I figure i would start with a hello to everyone. I post on other forums, so im quite familiar with forum etiquette (though this is the only photography forum i am registered with) Anyway, I recieved an old Pentax Spotmatic from my uncle along with an array of accessories including a 50mm f/1.4, a 150mm f/3.6, and an 80-250mm zoom (this thing is a monster) as well as a bunch of filters and a 2x & 3x teleconverter. After messing around with it, I noticed that the 50mm lens has quite a yellowish brown tint to it, the kind that screams old and musty. At first I thought it was just the prism, but after removing the lens, it was pretty obvious. Is there a way to clean the lens? I haven't looked at the other lenses since noticing this, so I'm not sure what their condition is. Also, whenever I set the shutter to 60 or slower and release it, the mirror stays up until i release the shutter again at a higher speed. I dont see any switch for a mirror lockup, so im assuming this is a defect. I've been wanting a fully mechanical camera for some time now, so if nothing else, this is a cool little machine to have.