[mohaine]

These are not cryogenic so something is probably possible but this would add extra weight/mass.

You do not want extra weight on your rocket. Every bit of non-fuel weight you add means you have to add extra fuel, and the extra fuel to carry the extra fuel along with any extra tank needed for the extra fuel. It gets bad fast.

It just isn't worth it when you can just add that weight as fuel that normally doesn't get used. Ideally would dump in the ocean (which you cleared) so it didn't matter (much).