Yes, oil, definitely oil.
Follow the general directions that are posted at Apache Poker.
I have several thousand Pharaohs, Majestics, and Milanos, and they most certainly benefit from oiling. I don’t know why some say they go back to their original state. Maybe those were earlier batches or something. But having bought repeatedly from the same distributor (and probably the same manufacturer) as you’ve got there, I am positive your chips will benefit from oiling.
It’s a *little* time consuming, but once you get in the swing of it it’s fine.
Use the oil-and-water method. Mostly water, just a little oil. Heat up the water periodically, and add more oil whenever it seems to be running low, every 50 to 100 chips.
If you see visible chalkiness, then scrub them one by one with an old tooth brush, holding them under the oily water. Then lay out on a towel. Then rub dry with a tea towel or similar. I do 20, 25, or 40 at a time. Can do maybe 2 racks an hour, maybe a little less, never really tracked it.
If your chips are not as visibly chalky, or you’ve oiled them in the past, then you can do it the fast way: grab a barrel in one hand, dip the whole thing under the oily water a few times, rubbing the edges to get them saturated, and allowing just a little water to seep in beteeen chips. Then set the stack on a towel, quickly rub each chip dry. It goes faster that way than if you are brushing each chip.
I’m currently oiling my whole cash super set. Sometimes I come to mixed groups where some seem to have been oiled before and some not. The newer / chalkier chips on separate out and throw I the tub for the individual brushing, and the ones that already have better color I just give the quick barrel treatment.
You won’t regret it. It’s not like you have to do it over and over… just when you add on, ideally.