saving painted design on hoosier style cabinet

I recently acquired a three piece set of Scheirich (Louisville, KY) cupboards, a center cupboard similar to a Hoosier, with two side cupboards. They are painted white with Dutch-style painted trim (hearts and comma strokes). It is stenciled on the back "Sweetheart" so I assume this was the name it was marketed under. The interior of the pieces are painted bright red. The paint is all original. By and large the set is in great condition, but is very dirty from living with an old man for about 25 years since his wife died. There is some paint eroded around some of the door handles. The handles are red plastic with a metal strip down the center. One or two are damaged.

Is there a way to clean this cupboard to make it look more appealing? I have tried washing it with Dawn with no success. Does anyone have a source for replacement handles for Scheirich?