Emblem nut sealer

image.jpg anyone know what is the proper sealer to use behind the sheet metal nuts on mopars?

I’m getting ready to install my brand new PLYMOUTH letters on the 66 Barracuda and of course Layson’s does not tell me I need new nuts. (Ordered letters 2 years ago, my fault for not checking I guess)
Anyhow, I can reuse the old nuts, but after scraping out a black tar like substance I’m thinking silicon is not a good choice. Maybe the strip caulk (aka: monkey $h/t)
I guess I can order the new nuts- just hate to wait a week for parts... or more.
Joe