I've never done any of the 'stop the threads' ideas, and have been happily prewashing my fabric for (oo oouch, I Really am old). I never do them in the wash machine though, just a good rinse in hot water at the kitchen sink, a quick wring and into the dryer they go. I'd have to rethink the sink if I ever bought more than 2 yards of fabric, but i don't, 1/3 to 1 yard is plenty for me.
good luck, your body will thank you. I did have to rewash the whole stash once when we had a roof leak. I just did it over a couple of weeks.