The badges can be directly painted over with acrylics, do a thick layer of the foundation colour...

Then express your own doodling on that little space large enough to be colourful, no worries...

If you can't be asked waiting for it to be dry, use they hair dryer ot expose them under sun...depending on your climate or weather ;))

To protect them to be lasting longer you varnish them with the varnish...nail varnish is ok, or water based varnish or "flatting"(pretty chemical though) ...Voilàààà... ^_^
Am curious about yours....