I’ve heard you can’t make a decent egg white foam in them.
…writes reader Owen. That’s another well-worn myth in the world of foams: that it’s impossible to whip up a good foam in a plastic bowl, or using plastic implements. The logic is that because plastics are so similar chemically to fats and soaps, they tend to hang on to trace amounts of them, foiling future attempts at foamery. There’s some truth in this. Plastic, fat and soap all share certain structural similarities. It’s also true that they tend to want to hang on to one another when they’re in close proximity, as anyone who’s ever tried to wash out a plastic salad bowl coated with oil can attest (it takes lots of soap and scrubbing, and even then you probably can’t get rid of it all). But unless the bowl in question is actually greasy to the touch, those minute amounts of fat won’t adversely affect the foam.