I accordian pleat my long fabric pieces in about one yard folds and then I safty pin all layers together in about 8 places. It takes large pins. It goes though the washer and dryer like this. Sometimes it is necessary to move the pins around about half way through the drying process so that you will not have any wet spots.

iF THERE ARE ANY HOLES I STEAM THE OUT WHEN I PRESS

I have stared surgeing my ends after reading about it here and it works great. I am sure zig zagint the ends would work too. And make sure when it goes into dryer you make sure it is not already tangled up from the washer.
Have washed my fabrics for 50 years and the surging best idea ever.

I have done this and it works great.

I wash all my fabric by hand in very hot water. I let it soak until the water is cool. This takes care of shrinkage and bleeding. I fold it accordion style into the water. When the water has cooled I hand squeeze it then hang to dry.
I'm lucky to live where we get lots of sun. Queensland is called the Sunshine state.
I always wash my quilts when I'm finished so that takes care of cleaning the fabric.

Prewashing fabric
 

I have washed pieces much larger than 3 yards, I hate to cut it as I would probably end up needing the larger piece. The trick to not getting tons of threads is to make a small triangular cut on each corner of the fabric. For some reason it seems to keep the fabric from shredding the pieces. I almost always prewash my fabric, I just like to be safer from fabric bleeding. Since we have to pay for each load of wash, I will sometimes rinse the fabric in the sink and I have been surprised when a lighter fabric is the one that will bleed - a good reason to prewash.

I also use the "snip the corners" method and it has always worked for me. I pre-wash everything, and after this last backing, I am even more inclined to do so. I lost a ful 10" on a 108" backing...not very happy, but at least it shrank before I attached it to the quilt.

I have always cut about 1 inch diagonal off of each corner too - never have problems with the tied up strings . . .

I would serge/zigzag the edges. I fold mine and put it in a large mesh washing bag. I use 3 color catches with darker fabrics. I do not tumble dry large pieces - for me that is when they turn into monsters. Someone told me to go to a laundrymat and put each large piece in a separate dryer - the tubs are bigger and there is less knotting. Never tried it that way. I wash in warm water, and wash and dry my quilt after binding - never had any issues - but I like puckering.

I was watching a Kaye Woods episode and she had a tip on washing big yardage (up to 15 yards) without it getting roped up in the wash.
You are suppose to open it up so the fabric is its full width then accordian fold it down the yardage so when you're done it's all kind of stacked up on itself about 12" wide I guess. Then using lots of safety pins, pin in the selvedge areas on both sides then wash it.
I don't understand how the snip the corners are suppose to work. I've never done it - but then I've also never done this Kaye Woods suggestion. I'm planning to try it out this week. I've got some yardage to wash ;)