Customer brought in a photo/sign that they'd had outside, then had framed with museum acrylic and spacers. After that, it was either put outside again, or stored in a roasting hot unit (or U-Haul truck?). The spacer has heated and bowed out so much over time, back and forth, that the inside of the acrylic had adhesive 1 1/2" in on two sides. Wouldn't be a problem, except an area at the top of the image stuck to the acrylic. We didn't know it had stuck, and didn't expect it to, being acrylic. When we took the fitting apart, part of the image (which I'd thought was a metal sign, but turned out to be paper surfaced), tore up. A section about 1 x 3" is plastered to the acrylic, which also has the goop from the adhesive on those two sides. It's also signed and numbered on the back. Oy.I believe WD-40 would dissolve the adhesive if the carrier has been removed already, an I don't think the solvent would attack the anti-reflection coating...But I'm not sure, so test it in an inconspicuous spot. Removing the WD-40 is the next challenge.