Stop using PVA on book cloth until you test it first
I ruined about 30 spines last month before I caught on. The book cloth I bought from a craft store in Portland looked fine, but the PVA glue soaked right through and left ugly dark stains on the outside. Turns out some coated book cloths need a different adhesive or a barrier layer. I started doing a tiny test swatch on every new roll before I commit to a project. Has anyone else had this happen with specific brands or finishes?