If you want temporary results mask 3 inches around emblems and plasti dip them.
If you want permanent, remove them sand them down and use primer then what ever you choose.
I used 3 coats black primer by duplicolor which was more then enough and looked great, then 2 coats plastidip metallic grey then 3 coats duplicolor high gloss.
They looked awesome but came off once I got new emblems.