Hi Julia, So sorry to hear about the cocoa butter staining your towels! I haven’t noticed that with any of my bath melts so far, but have to confess that some of my towels are hand-me-downs from my grandmother (who passed away over a decade ago!) so I don’t always pay close attention to them. Mango butter is a nice white butter, but the calendula will turn it more golden. Perhaps you could have an old towel handy for the first try, just in case!