Silicone seal, the white rubbery substance found around sinks, showers and bathtubs, can be a real challenge to clean. While mould can't grow on the waterproof sealant itself, moisture can ...

Practical, no doubt, but pretty unsporting, especially when it’s possible to cast custom lenses at home using silicone molds and epoxy resins. Possible, but not exactly easy, as [Zachary Tong ...