How many times have you seen a hollow chisel and augur black and blue from overheating ?
How many so called experts tell you to polish the outside of the chisel ?
How many times do you grit your teeth as the smoke and sound of squealing bare metal leaves you cringing ?
And they told you never use lubricant didn't they ?
Well they are full of sh1t.
Never ever polish the outside of the chisel.
All you do is ruin the correct ground relief and increase friction.
Now I got a massive bollocking as an apprentice for burning a chisel by the old mill hand. He gave me the oil can and said simply this. Start the machine then a quick squirt in the top. Don't worry about the oil getting in the mortise, the auger will keep pulling it up and the waste will stop it going in the mortise. As soon as it starts squealing, a few more drops to keep it lubed.
That's why his chisels were always bright and clean. The oil stopped heat and gum build up. Heat is the killer. Your chisels and augers will stay sharp far longer with a bit of lube. I use Castrol full synthetic 5w30.
The detergents keep the chisel and augur bright and clean.
Nothing is worse than bare metal on bare metal at 1500 rpm.
Compressor oil is to light. Regular motor oil works fine.
When the augur is lubed it runs smooth and quiet. Makes the machine a delight to use.
I leave the door open and the pump can at hand. Airflow also helps.
Sometimes I will hold a vac hose against the chisel as I cut to pull the waste out and cool the chisel on hard timbers. Every bit helps.
When I'm finished another squirt to wet the whole chisel and keep it rust free. Quick start and stop to distribute the oil.
No worries.
If your mortising really hard timber a little oil at the auger tip DOES help reduce friction without leaving residue on the mortise faces outside. So chill out. It's all good.
Some guys use candle wax but it doesn't last very long.
The other critical factor is feed rate. Go easy. Some guys think they are drilling holes in the road. Ends first, work to the middle.
Half steps last. Waste slot always facing towards you to minimise choking and easy waste extraction. 
Stop dry humping the slot. Mortiser abuser.
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