Rear axels rebuild. O1 S

[Meir]

Since all the axel boots in my car was torn up and I’m at 76k, I decided to perform a full rebuild including new CV joins and all 4 axel boots. At the same chance, I removed the secondary cats and planning on installing the bypass pipes. So if the cats are out, I thought it would be a good idea to remove the whole axel assembly from the car and work it on the bench.
Everything worked out smooth until I got to remove the axel from the wheel hub.
Man… this thing is stuck. After some lubrication and heavy persuasions from my hummer, the RH side came off. The LH side is still stuck and won’t budge. I hit it as hard as I can and it won’t even move a bit.
So, question # 1: can anyone give me a useful tip before I go and purchase a 10lb sledge hammer?
Question # 2: once I get it out, what can I put on it before I get it back on, to help me remove it in the future?
Last question:
On the axel I managed to remove from the car, I noticed that the outer CV joint (the non replaceable one) sounds like it’s got sand in the grease, when I move it around.
Any ideas of how to wash away all the old grease before applying the new one?
Thank you all in advance.