Wedge a crow between the knuckle and the BJ at the boot. You will most likely ruin your BJ boot.

The other option is a pickle fork.

A replacement BJ is $15 and relatively easy to remove when you have the subframe out (a 3/8" drillbit, grinder, driftpin, hammer, and 30 min or so).

When you're done, put antiseize on the stud.