The Ultimate Chalk is the Iron-off chalk that also can be washed and sometimes brushed off for removal. It’s our best! Use a Medium High to High setting on your iron with steam or dry to remove the chalk powder. There is enough to top off your pad 5 or 6 times and one bag will give you hours of transferring stencils. It’s hard to determine how many quilts you’ll mark given all the variables there are to consider but to give you and idea of how long this chalk will last, we like to say how long we can demo at a show with it. We demo at our booth throughout the show and one bag will last us well over 40 hours. You can safely assume a pack will get you through several large quilts if not more.