I've seen several suggestions for SOAKING old quilts in a bathtub of water.
I can see putting a quilt on a sheet in the tub - and running water THROUGH the quilt -
When it is soaking - that is an opportunity for stray dyes to migrate to where they might not be wanted.
Reason for this post:
I was just soaking some small pieces (thank goodness!) and I have migrating dye from one of them all over four of the five pieces - I did NOT expect any problems with any of them!