There is one method that seems to work best for trying to get that stubborn lid off of a paint jar or tube – and that is to run it under hot water for several minutes. The water needs to be really hot, and you need to be patient, holding it there for awhile to let the heat penetrate through the lid and soften the paint. This seems to work with all types of paint. This method is less likely to damage the paint tube or jar than pliers are. Sometimes pliers rip a metal tube.