An even better (if you dont use baby wipes) one than that is to get an old pop bottle (the smaller ones) and punch a whole in the cap. You can then (if you have PLENTY of time on your hands) thread the ball of string into the bottle or (easier) cut the bottle in half put the ball of string in side and then tape back up (having threaded the end up through the cap hole first ;) )
The string can then be dispensed as required and you will not either loose the end or get in a tangle.
I should point out that this is not actual my Idea, i saw it some years ago on GW.