Hi. I can tell you from experience - *only* hand wash. I was very tired sometime last week (and got lazy) - put 3 molds (2 tubes and a milky way mold) into the dishwasher - pretty sure it was the top rack - but it doesn't matter at this point. The two circular molds - one turned more oval and the other cracked. I can salvage the 'oval' one but even then it's got some odd indentations. It's not completely wasted but I would likely use it to color one kind of soap, push it out and then cut it up into chunks or shavings or something. The milky way mold survived (thankfully) but some of it got this weird foggy spots on it. Doesn't ruin the soap or affect the shape in the mold but it's no longer 100% clear all around. Lesson learned
Hilary