I serge the edges and wash in cold water ad dry med. heat..I iron mine and store them flat. I do not fold them.

I've done both - just throw them in the washer and use a lingerie bag. They don't fray much on gentle.

I often wash mine with my regular laundry rather than a large amount of FQs alone. They seem to fray less if there are no other stringy things in the load.

I don't. I just take my chances. I buy from reliable sources and so far it has worked out. PS For what it's worth, I've been quilting for 30 or more years.

"How do you wash your fat quarters"
Well first I get in the shower and wash my upper left fat quarter... LOL

Usually, I just toss them in with my bigger fabric pieces. SOmetimes use a lingerie bag. No sewing edges here-too time consuming!

Is the purpose of washing them to see if the colors bleed? I thought it might be preshrinking, but for those who line dry, that wouldn't be the case. I'm new to all this, so I'm wondering about prewashing my fabric and/or FQs. What made me think I might need to is I just purchased FQs to make pot holders and I know since I'll be washing them somewhat frequently and wondering if I should be concerned about shrinkage.

Two reasons to wash - first you don't know where it's been and what it has been treated with. Dead mice have been found in fabric bolts, plus the fabrics are treated with chemicals and I want to remove those. Second - shrinkage. I forgot to wash fabrics for one quilt and when I pressed the blocks a Robert Kaufman fabric shrunk so badly it distorted the block. I guess to remove excess dye, too, but I haven't found too much color transfer to my Color Catchers even with the load of dark batiks I did last week.

I put them in a small mesh laundry bag; then wash as usual

Thanks for the quick answer Irishrose. Time to wash my fabrics (eww on the mice and chemicals).

I soak mine in a little handwashing detergent in the bathroom sink, rinse about 3 times and lay flat on towels to dry. I try not to do too many at one time. Some people use a salad spinner to get water out of their precuts, but I have not tried that.
Hugs Pat