I have a collection of over 200+ batiks. I took on the huge job of pre-washing them all last winter and probably a good 1/2 of them did bleed - the blues were the worst. While I do not have any pre-cuts, I think that I would just gently put them in a pure white pan of lukewarm water with a drop of liquid soap and see if your water is blue. Rinse until the water is clear and then roll up in thirsty towels and then line dry - over an indoor line of some sort - or shower curtain rod, etc. Iron if necessary.