Scope problem

I have two scopes, one with a bigger lense (great for sniping) and one with a lense about the size of a quarter. The bigger one is missing a bolt and won't stay on my rifle right, and the smaller one has both of its bolts and stays on just fine but it is too hard to look through when I have my goggles on.
What can I do??? (Other than buying a new scope or new rings):shrug: