This window came to us caked with cement, and smeared with mud. It spent a good portion of its life out of sight. I had to scrub and dig out the cement until I had all the crevices in the glasses cleaned out. Then, I scrubbed the whole piece.
It took forever, but it was well worth it. Then, I repaired the broken pieces, and re-conditioned the leads and putty.
This piece is opalescent in the middle, and the borders and background glasses were French Craquel. It looks a little like cracked ice, but the wrinkles are deeper and sharper.
When it was finished it sparkeled like crystal. I didn't want to give it back to my client! But we gave it a nice frame, and off it went to its new home.