If you haven't used it in a long time or you have a mascara with an especially thick formula, there's a way you can thin it out so that it will distribute over your lashes evenly. Mascara can also thicken when it is close to running out, as the formula will often clump together on one end of the tube and become hard to get out. By using a method that gently heats the mascara tube, the formula will thin immediately and become much easier to use.
Fill a small bowl with very warm water.
Place the closed tub of mascara into the warm water.
Allow the mascara tube to sit for two minutes.
Remove the mascara tube from the water, dry it off, and use immediately.
Repeat the method every time you need to use the mascara, as the formula will thicken up again once it cools.