Bloody things! The ones on my Yota have maybe never been taken off and over here we drive through a steady (at least) inch thick of salt all winter so they where really rusted in.
Read the Toyota manual and it says to use a small punch with a point ground on it, hammer it into the slot to pop them.
Didn't work.
Read on Pirate...Use a BFH and a brass drift and wail the tar out of the top of the studs and they'll pop right off.
Ok...maybe in California...but not here. I beat on them fawkers for hours...tried everykind of penetrating oil...
tried heat...bigger hammers...nada...it wouldn't budge.
Go back on the internet...read where a guy tried all of the above and it didn't work. Says to use a small screwdriver and just tap it in the slot and the washers will pop right up.
Yup...tapped a little too hard and smashed the handle off the screwdriver.
Then I got thinking about the Toyota manual directions.
Got the small punch and ground a long, thin taper on it, much like a small screwdriver. Started tapping it in and BINGO...it popped right up. The rest popped up also.
Went to the other side that I hadn't touched yet and they popped right up too. Gawdammit...wasted a whole day tryin to get the arms off that little sucker.

Always a custom tool, eh!