It's so easy to be excited about making something, that it's hard to slow down long enough so that you can toss your fabric in the washing machine before you start working with it.  You can save yourself a lot of headache by pretreating the fabric first, otherwise, your new favorite pajamas can shrink after you've made them.  Professor Pincushion discuss why it's important to pretreat your fabric, different methods for pretreating fabric, and how to locate the laundry instructions on the fabric bolt tag.  You don't want to put in all the effort to making something amazing only to wash it once and then it's suddenly different than it was before and maybe no longer useable.  Start your project off on the right foot.