You can mount/frame glass or tin - no problem. There are a lot of ways to solve the problem, this is just one example. A small brass or silver wire will hold them in place and double or triple matt to clear the glass (tin only needs a single). Here's a series of my 8x10 Black Glass Ambrotypes matted and framed (37" x 17") wet plate collodion.
I have been using Scotch, "Acid Free" Double Sided Preservation Tape (#889) from Light Impressions to mount ambros to museum board and then overmatting with a window matt of 8 ply. They look fantastic and none have lifted. If you do want to remove them, you can. Although the mount will be damaged, the tape then easy comes off the glass when peeled with no trace.