Treating rubber seals. What to use?

As usual this time of year, I have loads of time-off.

So, was reading in another thread a couple of days ago about replacing seals around the hood, hatch, etc. Someone mentioned -- I think -- that treating them is a good idea to keep them supple.

Wasn't sure, but thought this merited a separate thread, rather than a detour in that particular thread...

Anyway :focus: What do you all suggest -- or is it worth it at all -- to treat the seals -- and what do you use?

Considering the seal angle, I was thinking fish oil ...but that might attract raccoons in my woodland hideaway.

So, also ignoring my Lancome products, what else might work?

And, would just rubbing it into the rubber be the best way to apply --- hmmm --- this is starting to sound like a job for hubby Kevin

Kristi