Heh, the are called cone washers. These are on a steering arm, yes?
The preferred method is to get a big brass drift punch (For this, I use a 3/4" drift) and smack straight down on the stud with the drift and a BFH. A few hits and they usually pop up loose.
If that doesn't work, I thread the nut on half-way, and get my air chisel. Use a rounded point chisel and hit it with a few bursts.
Toyotas use these on both the steering arms and the locuking hubs. I just had to remove 20 of them to rebuild my front axle last week. I use the chisel for the hub studs and the drift for the steering arms.
Obviously, make sure its alll wire brushed clean and some pb blaster doesn't hurt.