And since this thread is revived, I thought I'd post a recent confirmation of Elendil's use of the needle tip squeeze bottle:
http://www.e-cigarette-forum.com/fo...ed-siringe-sumtin-refill-cart.html#post462794
I like this method best on the 801/112/4072 atty/cartridges. Here's why..
Because the cart is so big one can vape off the top and then refill and vape that off, etc. etc. and sometimes never let the juice in the bottom of the filler to wick upward. As a result - I noticed this on an original 'Virginia' prefilled cart, that juice esp. if tobacco based can get quite strong if it sits in the cart too long. Virginia is a pretty good tobacco based juice - a flue cured taste with a mild tobacco when fresh but if it sits at the bottom of a 801 it can get nasty.
I had a straw mod and I tried PTB on the Janty Stick and they work well but if you're topping off you're still leaving some juice at the bottom. The needle tip fills from the bottom up and pushes the juice up from the bottom on each 'top off', actually 'bottom off'. And so the effect of having bottom juice there for a few days doesn't happen. I'm finding this works better than the straw mod. If you're a PTB fan you can still use that. The needle tip link is in Elendil's post.
The same 'mechanics' aren't as important with the smaller carts where you can vape them dry in one session... something that simply doesn't happen with the 801. Well, it doesn't happen often

Esp. when you have 2 going - one at the computer and one at the tv/living room chair.
Hope someone finds this helpful and thanks to Elendil or whoever might have been before him to point out this method...