I do this with my pre-cuts all the time. First I put them in the washer in a lingerie bag and let them spin, but don't put them in the dryer. Then I iron them on the cotton setting with no steam, letting all of the steam originate from the fabric. This is best for those projects where exact measurements are not critical like a jelly roll run, because some of the fabrics narrow down to less than 2.5".
I also do this with fat quarters and pieces of 2 yards or less (bigger than that is difficult to iron), because with 100% cotton the dryer tends to set wrinkles.