The problem is that coverslips are not clean, they are very dirty I would say... I bought a new box of coverslips, took one from the middle of the pile. All of them look like on photos below - there are somekind of crystals on their surface. it is possible to remove them but it takes time and is something that one doesn't want to do... (;
It is not a first time when I see those crystals, moreover - I'm not the only one who has seen them on coverslips.
Does anyone know a store where I can purchase coverslips that are confirmed to be clean?

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