I've never had a failure with these markers, and I've been using them for years. I'm not sure how everyone else removes the marks once the project is finished, but I ALWAYS soak the project overnight. Usually, I fill my washer and add some detergent (or whatever you use), let it agitate for a minute to be sure every part of the project gets saturated with water, then turn off the machine and let it soak. Next morning, I run the washer.
I use the same method when I use the blue markers. I've ironed over both the blue and the crayola washables, as well, and the marks have always come out using the overnight soaking method.
Of course, if you have any doubts at all, take the time to test.