Go to your local Hobby Lobby and find acrylic paint by DecoArt - Americana series. Find a base color that is close to what you have on your ribbon cover (take that off the machine and into the store).
Then go to the aisle where they have Testor's paints (in a flat finish) and find some colors that will help you get to the base color on your machine with some custom mixing. This will take some trial and error to get the mix just right. I use areas of the underside of the machine or the ribbon cover as my "test areas".
If the original crinkle paint is scraped away and there is bare metal, I use latex caulking (with zero % silicone in it) and dab on the latex with a q-tip to recreate the crinkle texture. Let that dry for 2 days or so. For little chips that will fill in with paint, I do not apply any latex caulking.
Then I will mix up small amounts of the Hobby Lobby paints until I am happy with the mix/color and then use a small artist brush with its bristles cut off, short... and apply the paint in a dabbing technique and not using brush strokes. I use a dry paint brush with not a lot of paint...sometimes dabbing my brush dry on a paper towel before applying the brush to the metal surface. I apply the paint very lightly and add more paint 2-3 more times with some drying time in between...again dabbing with a dry-brush. Once the original area is touched up, I will dab on some more paint very lightly and radiate out away from the area of damage/repair to help blend in the new paint (color and texture) with the surrounding original area of paint.
Here is my S-C Tower President which needed some touch ups. You cannot see the areas of touch-up after I was done. I started with "Khaki Tan" from DecoArt and added very small amounts of yellow and some rose "flat" paint from Testors until I was happy with the mix.
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