Instead of washing out canned soup containers and peanut butter jars, consider letting your worms do the work for you. Sometimes feeding is just that simple.
In the past, I've always buried the food in the bin, which helps prevent bugs. Since worms prefer to feed from the top, I'm trying a new approach of feeding from the top and covering it to prevent insects. In one bin, I'm covering the food with a plastic trash bag. This has worked very well as the food was eaten much faster.
In the other, I placed a rotting tomato on top of the bin and covered it with a paper coffee cup. I would say the worms really like this way of feeding, wouldn't you?