This is an excellent opportunity to remove the various types of adhesives on these and get m into shape to re-mount.
Here I am removing contact cement from a tile. Contact cement, asphalt and tile adhesive!
After pieces large areas together, I intend to get interior reinforcing done. I will also take up bad original fits by bridging gaps where the tiles shrank in the kiln.
Here's me 'buttering up' the interior of a tile to bridge gaps before the curved top surface goes on.