Use a paint brush to apply the paint thinner to the paint on the chair.
Wearing gloves, use a metal scrubbing pad to rub the paint thinner into the aluminum chair.
Rinse off the paint thinner using water. Be careful to rinse your chair off somewhere where plants and animals will not come in contact with the thinner.
Repeat steps one through three until you have removed all the paint from the chair.
Rinse the chair thoroughly to remove any excess paint thinner. Leaving paint thinner on the chair for a long period of time can cause damage to the chair.