There was a post about washing the canvas used to make the iron boards Jenny demonstrates. I bought duck canvas, washed it and then put it on my board. Worked great. However...it got dirty. Can't figure this out as I only use it for pressing quilt pieces and dont' remember even using any black fabric for the last year so I dont' know how so much black marks and smears got on the yellow canvas. I scrubbed but they didn't come off. So I just took the canvas off the board, washed it again. pressed it and put it back on the board...and it worked great! No shrinking and the stains/marks are gone and it is beautiful yellow again!