Thank you for the very interesting replies!
So, controlled atmosphere and humidity seems to be the answer for the conservation in large museums.
It makes perfect sense as I don't even fathom how would be possible for large museums with thousands of pieces to re-wax periodically all their huge collections.
Thank you Alan for your insight! I am already using your "oil & foil" method on my krisses and the pedang I have and it works perfectly.
For the other blades, which I normally keep on display unsheathed, I use Renaissance Wax as it is quite easy to get, and while a tad pricey, one jar lasts quite long.