There are a few things you can do to get clean paint lines out of your painting. The first is to use a hairdryer to dry the paint off. This will remove any oils and make the line more visible. The second is to use a vacuum cleaner and bucket to suck up all of the paint that has built up on the surface. This will also remove any dust and dirt that may have been on the painting. Finally, you can use a vacuum cleaner with a hose to clean all of the surfaces in your room, including your paintings, furniture, and flooring.