You have a mess for sure. It can be fixed but will take time and patience to cut all the dark threads away from the white.

yes, trim the threads. Now you know to quilt first before washing. I'd also suggest you check to make sure no seams opened up in the washing too.

Sorry you are having problems with your quilt. The long seams could be folded back. Lay a long ruler over them keeping the 1/4 inch seam and trim with rotary cutter.

The piece that disintegrated can be carefully removed and replaced with a new piece.

best wishes rescuing your quilt.

Exactly why I would never wash a quilt top until totally finished, no matter what.

The quilt actually looks like it held up quite well. I concur that you need to trim any threads that might show on the white, which means most of them. Press it carefully from the back, then the front.

FYI- I'm trimming it with scissors or nippers in one hand and the vacuum cleaner hose in the other. If I've got to clean the Aegean stables, I may as well share the data from the research. Experimented with using electric hair clippers, which worked well, but it was really easy to accidentally clip a seam allowance. Hahaha, now that's rubbing salt in an open wound.

I'm just a little less than half done.

Good luck with your trimming. Been There, Done That.

If your schedule allows, just take it a little at a time.

I would trim all the threads - you'll feel better, it will look better, and quilt better. Beautiful plaids - it will be a beautiful quilt!

I have a top from the late 1800's that I washed. I wish I could have seen the look on my face when I realized what I'd done. I get it out about every 5 years and work on trimming and pressing.

One totally fun thing you could do is quilt it that side up, just press it good so it lies flat.
A one of a kind rag quilt. Quilt it about 2" apart. Straight line quilting would go great with a service quilt!