I have used duct tape to fashion a custom solar guard for my nose when I didn't have any sunscreen handy. It taped onto the bridge of my sunglasses, and the nose pads resting over it helped keep it in place. I think it had an UPF factor of 100.
I was going to make another one to wear with my Cocoons. But I might try a buff instead. The old schnozz seems to attract more than its share of solar radiation.