Yep, acetone is it. It'll do it's thing quicker if it's warm. Place the bowl of acetone over/in another bowl of warm water.
DON'T KEEP TAKING THEM OUT TO CHECK - THIS WILL SLOW THE WHOLE DARN THING DOWN.
DON'T "HELP" THE LAST BITS OFF. Acetone will dissolve every last bit back down to the surface of the nail. BRILLIANT. So many people get impatient and it's always zone 2 in the middle that's left - this of course is where you had the most product. By "helping" this off, ie with orange stick/cuticle pusher/black and decker/teeth you may as well have ripped them off instead! Those bonds are still there and the only thing that knows how to unlock the key safely is ACETONE.
Once out (maybe 25 - 35 minutes - maybe more - be patient!), buff and throw as much fine grade oil (ie Creative's Solar Oil) into the nail as poss.
little tip i learnt along the way for soak offs :
Tear off 10 squares of foil
cut 10 squares of lint soak lint in a dish of acetone,with a pair of tweezers pick one up at a time.place on finger wrap foil around and continue on following 9 fingers this will take a good 30 mins ,however if only several need to be done you can work on the rest its much quicker,I usually use a china dish ,like an egg cup you dont need much acetone hope this helps and you can understand it