I have had problems with the mini blinds and Sharpies. But not the knives. I think the mini blinds get a layer of gunk or oxidized vinyl on them that comes off and takes the Sharpie with it. I think that's why pencil works better on the mini blinds. The pencil wears through the layer. And the knives are new and completely clean and the Sharpie sticks really well. But it still sun fades or weathers.
