[header] How to soften a paintbrush [title] Squirt a pea-sized amount of lotion into your hand. [step] You can use any type of baby lotion. However, if you don't have baby lotion, any hand/body lotion that you have in your home will work. 
The lotion ingredients aren't important, but you should try to use one that dries cleanly. Any greasy residue may damage the bristles.