I received some old Win 3.11 installation diskettes from a colleague. These diskettes are the perfect size to be repurposed into coasters for your mug. However, they are not waterproof. I found silicone molds on AliExpress designed for use with epoxy.

It took several iterations to determine the optimal process for creating aesthetically pleasing coasters. The epoxy is quite thin immediately after mixing, and this thin consistency tends to damage the label on the diskette. To mitigate this, it is advisable to initially fill only a thin layer of epoxy and allow it to bind for a while until it becomes slightly viscous. Gently press the diskette into the epoxy, ensuring that the surface is well-bonded. Be cautious to eliminate any air bubbles. Allow it to cure for a bit before filling in the rest of the mold. Gentle jiggling of the disk can aid in removing any remaining air bubbles.