Hello, I am an Audiologist. Welcome to Fluther.
The ValSalva maneuver can cause damage to the delicate structures in the ear if the air pressure is forceful. However, many people are able to do it by very gently applying pressure and increasing it slowly until the ear pops. If you have a history of ear injuries or surgeries, then the risk for damage is greater.
Applying heat to the ear, such as a hot water bottle, can help relieve some of the discomfort. However, the air and sound pressure form a hair dryer (as suggested by @JasonsMom08) are potentially dangerous. The Sahara DryEar is designed to have safe temperature, air and sound pressure levels.
To help relieve the pressure, you might also try decongestant and/or antihistamine medications; but these are not safe for everyone, so I would recommend consulting a physician if you are unsure about potential interactions with any medical conditions you may have or other medications you may be taking.