Use your ladder to reach your gutters and take them down. Follow proper ladder safety, and have someone nearby to help if you encounter any safety issues.
Use the back of a hammer to pry out the aluminum spikes that hold the gutters to the trim of your home. Take each section down separately to avoid larger sections falling unexpectedly.
Check your gutters for any chalky film that shows that zinc may have formed on the metal. Sand any zinc formations with fine-grit sandpaper.
Dip a rag in mineral spirits, and wipe it directly onto the gutters. Wipe all of the gutters down completely with the mineral spirits.
Mix water and dish soap in a large bucket (5-gallon is fine) until the water is sudsy.
Dip a bristle brush into the soapy water and brush the gutters gently to clean them.
Allow the gutters to dry completely and apply your primer with a paint brush. Cover the entire outer surface of each gutter with a coat of the primer. Allow the primer to dry.
Paint the gutters with your paintbrush and latex paint. Allow the gutters to dry and re-hang them. You may want to use new aluminum spikes, as the spikes may have bent or become warped over time.