Not to worry. If you’ve got a teaspoon or tablespoon around, you can use them to measure cupfuls and vice versa. Start the day smarter. Get all the news you need in your inbox each morning.

1. Place 1 tablespoon of water in a small plastic cup. Add ¼ teaspoon of borax. Mix until as much borax dissolves as possible. This is your borax solution. If you would like your slime to be a certain ...