Paint an acrylic base coat over the molding using a paint brush. The base should should be the lighter of the two paint colors. Allow the base coat to fully dry.
Paint on the second coat of paint over the base coat with a paint brush. This second coat should be the darker of the two paint colors. Do not let the second coat dry.
Dab the molding with bunched-up plastic bags. The plastic bag will remove spots of the wet second coat so the base coat can be seen. Change the bunching of the bag regularly to create different patterns. The plastic bag dabbing should be strong to create a good distressed texture.