@ ocean
bro, another method is a bit difficult but it may help... dry ice has a temp of -78.5 deg Celsius, n it's handled with special care.... if u place dry ice for say 30 sec, it makes the metal sheet to contract n automatically dent comes out without affecting or scratching the paint.....
now, the point is from where this dry ice'd b found so search at www.yellowpages.com.pk or google.com abt ur area..... rite....
but there's a condition, i asked one of fire extinguished dealer to bring me the dry ice, but it was not cooled upto -78.5 deg, it was near 20 deg, coz the guy was touching that with naked hand.... so, this temp'd not help to contract the metal sheet properly n dent will not vanish...
make sure its optimum temp....
he said me that it was Rs. 140 per kg....
n plz handle with care, coz it creates cold burn if u'll touch it with naked hand....
after getting ur job done, plz do tell ok..
one thing more, u may find dry ice videos on www.youtube.com, so for reference do watch some...
BEST OF LUCK bro...