Review on Better18 Erasable Temperature Disappearing Refills by Wendy Rodriguez

I tried using a white marker almost immediately upon receipt; realize that it takes time to be visible. I couldn't show anything to show some red but it took a long time and wasn't consistent. Black and blue were worse. Since then I've tried to keep her down, warm, cool. . .every possible situation and there were no changes (can't use any of these for a simple project). I see that the return period has expired. How really? They have a very short shelf life, even if they are not "used". This is more likely to happen on eBay than Revain and I'm really surprised, especially to learn that I'm not alone (similar reviews I saw before buying but believed in Revain and the product).