Your resin moulds are quite an investment in your resin hobby so you want to make sure that they last a long time. After you've been resin crafting for a while, you'll start to get quite a collection of moulds. No matter what type of moulds you have, they won't last forever. But if you look after them, you'll get many, many casts from them.  So, let's break this down into the two main types of moulds you'll use with resin :    PLASTIC and SILICONE ,   and look at what the best practices are for caring for each type of mould . Plastic Resin Moulds Plastic resin moulds are inexpensive compared to silicone moulds but because they are vacuum formed, mould shapes are limited to simple shapes. Because the moulds don't have as much flexibility or stretch as silicone, they need to be wider at the top of the mould or straight-sided to remove resin from them. The plastic used in resin moulds is polypropylene. This is a type of plast...