Hey Ashley333- it's pretty easy. The way I do it is:
Materials needed:
Wash away stabilizer to use for the outsides of your crumb sandwich. There are a number of different kinds of wash away stabilizers. All are made of something like cornstarch and they dissolve pretty easily in a sink full of water when you're finished stitching your project. Some stabilizers are very sturdy and others are flimsy almost like plastic wrap. When I'm making scarves I use 2 types: Sulky Sticky Fabri-Solvy and an inexpensive wash away stabilizer by H.B.I. Products that I get from Amazon.
I use Sulky Sticky Fabri-Solvy for the bottom of my crumb sandwich- it has a release paper that you pull off to expose the sticky side. I cut it to the size that I want my finished scarf to be- usually 6" by 4 to 5 feet. lay it on my sewing table with the sticky side up and lay my crumbs out on it about 1 layer thick, overlapping some to make sure there aren't any gaps. Once that's done, I cut a piece of the other stabilizer that doesn't have any sticky and lay that over top. I usually pin it along the edges to keep it in place. Then I sew all over it in a grid pattern making sure to catch all the small bits of fabric in the grid and also to cross every one of my stitched lines. Then I sew around the edges twice- again making sure to catch the stitched lines.
When the stitching is done I swish it around in tepid water in my bathroom sink until the stabilizer has dissolved. Hang to dry. It will be stiff once dry due to some residual stabilizer. To remove the rest of the stabilizer I throw it in my washing machine on a regular cycle and then run it through the dryer on normal heat. What comes out is a nice, soft drapey piece of fabric.
Rob