Fitting 33's+ What did you use to protect your pinchweld from rust?

I'm about to cut and hammer down my pinch weld and I've seen some people use a spray, maybe just a basic spray rust blocker? And I've seen one that used like a pump grease type fluid to cover it in a video, but I wasn't sure what exactly it was. Anyone help what's the best to protect? Thanks

 

I'm going to use some rubberized undercoating. @boogie3478 here made this video on how to do it.

https://youtu.be/LdpHCZTV6o8

 

Just make sure that the surface you plan on spraying the rubberized coating with is super clean ... otherwise it will just seal that crud against the metal beneath which is not good if there's any salt or other corrosive materials trapped there.

 

Thanks for the tip!