Batman Cowl Lenses

Does anyone have any good techniques for swapping around lenses in cowls? I'd be interested in having a white pair and also a red pair but I want a simple way of doing it. I'd seen someone (possibly on here) had created a masquerade style mask to sit inside their cowl with the lenses on and that seemed like quite a good idea (depending on the comfort level I guess). My only other thought was some kind of Velcro solution so they could be swapped out but I want to make sure it's comfortable without the lenses as well.

My favorite method is to use magnets. Small, thin neodymium magnets are pretty cheap around the web, and a few sets of those make swapping lenses out very easy. I will typically attach a small section of some kind of rigid material to the outer edge of the lens (Worbla, sintra, etc.), glue one half of the magnet to that, and the other half to the inside of the mask/cowl.