removeing door hinge bolts??

Hi, I was hopeing that someone may be able to help with some advice on how to remove the allen key headed bolts on the hinges of my rear doors as they do not seem to want to move. I have tried using an impact driver to no avail and i am now out of ideas short of heating them up which will trash the paint. any advice greatly received. thanks jt.

I use a hammer and chisel to loosen then - then replace with newor good used - I can supply both

Cheers

Rich

HI, THANKS FOR ADVICE, I WILL GIVE IT A TRY IN THE DAY LIGHT AND SEE HOW I GET ON, ITS BEEN DRIVING ME NUTS.
CHEERS,