My husband has some over 25 year old secondhand army boots. They are his favorite boots for walking, hiking and gardening. They fit his feet perfectly. You can imagine the state of the poor old things.
Years ago they became very ugly, and we bought some paint. I don’t know whether the same product is stil available, but I know for sure there are simular products for sale. The product I used is Tana deep cleanser and leather dye in the colour black. This morning I painted them again.
At first I cleansed them with some disposable cleaning whipes and let them dry in the sun. After that I stripped some ugly spots from the old paint with the deep cleanser, and let it dry again. After that I protected my clothes and I protected my table with some newspapers, so I could paint without being afraid for splatters. I did shake the paint, so the colour was evenly spread and homogene in the bottle, painted the boots and let them dry throughout.
The boots are now black again, even with the leather still being damaged. And my husband is very glad that he can use them again without being ashamed with the appearence of the boots.