Our church has an outreach group "New to You" ... where they take in clothes that are in good shape and sell on consignment.
They only sell garments that are in perfect condition - any rips, buttons off, etc they divert to other charities, and some go into quilts (donors know how this works before they donate).
They have been making tons of quilts from the clothes that aren't resold - and lots are jean quilts. Usuallly they cut the garments into 9" squares. When they're cutting up the jeans, they often end up including the pockets - these make the most awesome quilts! Many of these end up being given to Mission services, go to homeless folk.
Have done up quite a few of these quilts, they use every kind of fabric - even crimpolene!!
The ones from jeans are a favorite - they will mix various colours of denim, from skirts, shirts, pants. They're wonderful! They can be very heavy - and are good candidates for 'rag quilts' - the frayed edge - layered with flannel. And they will mix other fabrics in with the denim - similar weights - also work out very well.
I haven't actually cut up any of the jeans, only sewn the squares together. They have a specialist who can whip through the jeans to get the most fabric out of them. Seams are left as they are (placed about 1/3 or 1/2 of the square).
I've been collecting my kids' jeans as they discard, but these are still on my 'to-do' list!