If your balsa is not flat you can sand it flat.
Finish with 2K 3M paper dry should do the trick.
Any coarse, medium, fine sand paper progression
will work. I have used my DMT on my "Green monster" balsa
hone to level it.

If your CrOx is powder mix a bit with mineral oil
so you have a paste as thick as tooth paste for
balsa (use CrOx and kneads foot oil on leather).

If you CrOx is a soft crayon that you can wipe on
the balsa -- go for it. Start with some XXXXXs
and rub it in.

If your CrOx is hard wax bound for buffing wheels
crush or file it and soften with a bit of anything
that softens it, even WD-40 might work. Not all
CrOx has the same grit you may find that you
want "the good stuff" that is about 0.5 micron.

Yes olive oil works, kneads foot oil also works
as does mineral oil. Just use small amounts...
small amounts multiple times as needed....

Apply in small amounts. It does not take a lot
and as it gets grey with steel add more green
stuff as needed.