Here’s the situation: you want to buy a nice shirt with sharp, sturdy collars. After several wash cycles, those collars go limp and even start to curl. One quick solution is to use collar stays. these are flexible strips that are inserted into the collars to make them look rigid and solid. collar stays can be made of plastic or metal in various lengths and sizes. Some quality shirts have little slits inside for the collar stays, so that you can take them out before washing.