Stop using cardboard shims and upgrade to Trim-Tex Shim in a Box.
Unlike paper-based shims, Trim-Tex shims are made from PVC and do not act as a food source for mold. The shims easily staple to wood studs and may be installed with spray adhesive in commercial applications. In addition, Trim-Tex shims have large holes that allow stud adhesive to effectively bond the drywall to studs.
Shim in a Box comes in 48" strips that can be scored with a utility knife and snapped to custom lengths or cut with snips.