The Workman repairing the tile in my shower put caulking down the drain. It solidified in the PVC pipe and the shower will not drain. Is there a way to dissolve the blockage without harming the PVC?
That is my question as well. Either way, DO NOT use any caustic chemicals. Call a professional in and see if they can remove the blockage without harming your PVC or ABS drain lines.
Not an expert, but I would probably try calling a professional sewer snaking company. Their snakes have cutter ends (for tree roots, etc) which might be able to cut through the grout.
I think a strong acid might soften the grout, but it might also damage or destroy your pipe.