I did it with the boiling water, but god, it was PITA! I bruised my thumb in the process. Putting the cap back on was tough too but not as tough. I just wished I'd apply some grease to it to let it slip.
boil it for like 5 minutes then wrap a towel around it for a grip....you gotta do it when its real warm and it should slide right off............... i remember doing this mod at 3 am cuzi saw it online and just had to try it right then and there...... and i love it