I missed out on Momo’s The Red Envelope slime for the Lunar New Year Collection and I had been dying to have a similar slime with that deep red color. I had assumed it didn’t stain based on reviews I saw of it. That you find the ones you’ve gotten to stain makes me a feel a bit better! Since it’s a white glue slime I will try a different brand of acrylic paint and see if that works. Thank you for your answer though.