These small, natural latex rubber socks are excellent for sealing partly used tubes of caulking, replacing lost caps of glue bottles or line chalk containers, etc.
Made from thick rubber, they seal well on nozzle diameters from about 1/4" to 3/4". Since only a part of the nozzle has to fall within this diameter range, it covers just about everything from toothpaste-type tubes up to quart glue-bottle tips.
These are a much better solution than putting a nail or screw in a nozzle tip. Also handy for capping the air inlet on air tools. Package of 20.