There is no shortage of Maine RV dump stations around Skowhegan. If you're there at the right time, you can catch the oldest state fair in the United States.
Dump stations have a drain cap that covers the sewer and drain outlet. You need to close the valve on the tank, take the cap off the sewer and push the hose from your tank into the outlet. Once you turn the valve, the tank will empty the blackwater.
You should empty the tank when it reaches 2/3 capacity. If it goes any higher, it can overflow.
Dump stations generally charge users for their services. Some campground stations offer this service for free if you spend the night there.
A RV dump station is a facility that lets you empty your holding tanks without getting your hands dirty. It also uses sanitary methods to dispose of the waste.