HELP... 2 yr. old pushed in the dust cover

I tried the vacuum-cleaner suction trick, in 2 or 3 differant iterations, but the suction is inadequate to pull out the center convex dustcover part of the 6" Dynaudio driver. I tried taking the driver out, but the affected part of the driver is not acessable from the back. Thinking of trying duct tape, then carefully removing any adhesive residue with appropriate solvent. I'm hoping someone has an easy fix for this!