Try putting the smaller pieces in a laundry net next time.
Or just hand wash them and let them air dry (of course, I'd never in a million years do this myself because I'm too lazy).
Or safety pin the pieces together first before tossing them in the machine.
Or if it's a fabric swap, wash the bigger piece or fabric and THEN cut the swap size block.
This is why I never do any swaps or round robins anymore. ;)