I must be the one in a thousand that has not had a good experience with Imperial sizing wax.
I have a small press (the RCBS Jr. for those of you who can remember it) that does not have the power of the modern presses. This means I can really feel the pressure it takes to full length resize the larger rifle cases. My two-cents worth is this:
The absolute best lube for high pressure forming is Rooster CFL-56 case forming lubricant. Goes on the same way as Imperial, but works 1000% better.
If you are sizing small (223 Rem. or so) cases, almost any good spray lube will do and is much quicker. Use the bag method. I use Hornady One-Shot.
While Imperial Sizing Wax will not dissolve in water, it will dissolve in naptha (common lighter fluid for your Zippo cigarrete lighter, or available in Home Depot paint department).
I use my "liquid Imperial" on a small round brush to lubercate the inside of the case mouths -- works better than anything I have found.
Take about a quarter teaspoon of Imperial sizing wax and mix with one ounce of naptha in a small glass bottle. You can use a regular hair drier to heat the mixture up to 130 degrees F or so to make the dissolving go faster. After use be sure to cap the bottle with a tight fitting cap so the naptha won't evaproate.
Dip a nylon bore brush that fits the case neck gently into the Imperial/naptha solution, and make one pass inside the case neck (a Q-Tip will also work). Let dry for ten minutes or so and you will have a perfectly lubed case neck with minimum friction when withdrawing the expander button.
Best neck lube I've ever found, but Imperial has just not worked for me on the outside of the cases when full length resizing large cases on my "under-leveraged" press. Anyone out there using the Lee Hand Press on larger bottle neck cartridges, the Rooster CFL-56 will amaze you.
And no, I have no connection with the Rooster company. Just have tried almost all lubes from STP on...