I loved the blue foam for quite awhile in the beginning because I was comparing it to the polyfill.
However, I changed to using Fluval and NO leaks, long vaping, and flows juice dry. It is also available at pet stores.
I peel a "slab" of Fluval off one of the chunks...the thickness of a cart narrow wise (1/4+ inch). Cut a piece in a triangle with the widest part a little wider than the cart longwise (1/2+ inch). The other 2 sides are long tapers down to about a point (1 1/4 inch for regular cart and 1 3/4 inch for mega carts).
It is important to cut the triangle as an Isosceles triangle and not as a scalene triangle.
Next, take the pointed part about 3/4's of the length and twirl it to make a long point. Snip an 1/8 of an inch off the bottom tip to make it flat. Fill cart to almost top (on a 510 mega cart it takes 21 drops). Stuff Fluval into cart as far as it will go and pretty fast. All the juice is absorbed. Trim off little hairs and excess, if any, that is sticking above cart top so it is flat. Add a couple more drops and put on atty.
Whenever you want to re-fill it, pull Fluval out with tweezers and add juice (I add 16 drops to mega cart and 6-8 to regular cart) until it is 3/4's full. Put Fluval back in quickly and top off with a couple more or so drops until just starts to pool.
When it's done right, takes about a minute and lasts for quite awhile with excellent taste, vapor, and NO leaking with eGo standing upright, even all night because I fresh fill them so they are ready to go in the morning.
I have a bunch of little triangles cut ready to go as I like to change them out fresh every 2-3 days when they stop letting the juice flow smoothly. I have washed them and used them again but it is much easier to just start fresh each time.
I tried everything with the Blue Foam; Scotty's, exact measurements, spring, straw, pin, rolling, wading, etc. and nothing worked without leaking at some point. I got tired off having juice on batts and me so tried playing with the Fluval someone PIFed me.
Sorry for jumping in on your Blue foam thread and after reading all the comments, I had to share what has been working for me for months now.