When I refill should I blow off all remaining pressure or take it in as is or
does it not make a difference? My bottle is empty at 14 lbs. but still has
500 psi.

 

Do not waist any nitrous by blowing it off. You can have 1 lb. put in a bottle to top it off so there is no issue have some or a ton of nitrous.

 

It weighs empty because all remaining nitrous is in a gas or vaporized state which doesn't way anything. But when cooled what little bit thats left will turn back into a liquid. Or when you have it filled and the bottle is pressurized it will turn to liquid as well. Anyhow that bit thats left over is nitrous and you are just wasting it by letting it out.

 

You can do it either way. They can top off a bottle or you can empty it.

I always like to empty it in most cases but thats me.