This is the same method I use and it works for me.

Someone referred to Coats & Clark thread as "crappy thread" - what kind of thread do you use to sew with? I'm not trying to hurt your feelings, I'm just wondering. I tend to sew my pieces together with really inexpensive serger thread spools, but use embroidery thread to do my quilting with. Do you have any suggestions that work better for you?

I also clip a triangle off of each corner, then simply clip any (usually only a few) frayed threads, as it comes out of the washer.

Go to website of Superior Threads, based out of Arizona. You will get a boat load of information about thread.
I personally have been in your shoes, and used super cheap serger thread, and what ever else was handy. Do you clean your bobbin case when you put in a new full bobbin, ever wonder where all that lint comes from.....it comes from your THREAD...and can really damage your machine. I now only use the So Fine #50 from Superior and I have next to NO lint anywhere...it sews beautifully and I know the thread will last as long as the quilt fabric...

I have some 20 year old quilts that are used almost everyday - they are our 'couch quilts' - used Coats & Clark dual duty thread (cotton over polyester) - the thread worked great in my machines - it's held up great in the quilts -hasn't 'cut' the cotton fabric - threads haven't broken -

What is the problem with it - other than that it WAS available at stores like WalMart, Hancocks and JoAnn ???

If any one wants to get rid of their old, awful, crappy, cotton-covered cotton over polyester Dual Duty Coats & Clark thread, I would be happy to pay postage costs to 'take it off their hands' and relieve them of the torture of using that kind of thread.

C&C cotton thread is strong thread but is 3 ply, too thick for me for piecing. It tends to have a lot lint. I use a bigger needle for 3 ply, 90/14 and use it only on my machine that has outside threading. Lint is a killer for machines that have inside threading. Serger thread is not made for piecing, it's too weak when used off one cone for a seam. Three or more cones sewing together makes the surged seam strong. I do like the C&C bobbin thread. It's 80wt and works great for machine quilting on white fabric. It only comes in white.

I just tried using my pinking rotary cutter on fabric before washing and it works great. Very little raveling and no tangling.

I use mesh laundry bags for the washing part and take the fabrics out of the bag for the dryer. If you have lots of small pieces hang them to dry instead of the dryer. If you don't have an outdoor clothesline try over the shower rod and towel racks.

You don't wash the pre cut fabric. I don't wash any of my fabrics except for reds and flannel. There is no right or wrong. I use to wash everything but not any anymore and there is no difference. I do wash my finished quilt.