Give 100 cpu load for quite sometime (depending on the room temp as it is winter) , observe the temp. if it is above 65 degree then quickly shutdown and try removing the HSF.
@suyash, are you sure the processor is in working state? cause if the processor was forced remove without unlocking that "stick" lock, the pins can get bend. check it first. if everything is ok, you can place the processor in sunlight for sometime, the TIM will get soft & processor can be removed from the old HSF.