I like the blue foam too, if you need specifics here is the brand to look for at the fish area of any local pet store or petsmart/petco. They come in 3 pack, and they are huge pieces of blue foam that should last you a long long time, just rinse well with warm water before use, and cut small sections slightly larger than your cart, and insert into cart, drip till it's full, you may have to adjust foam to help liquid soak in the first time.They seem to hold up a long time and clean up easily. I have had no problems with it wicking or changing the flavor of my liquids. Great stuff, here is what to get:
Marineland brand
Bonded Foam Sleeve
style: U
so you can see the package:
Marineland Rite-Size U Bonded Foam Sleeve Aquarium Filter Sleeves
I have also found that a little alcohol soak and a quick warm tap rinse, then cool blow dry works great until the coil gets so gunked up that it won't wash clean any more, then I use the mod where you pull the mesh/bridge out to expose the coils, and I use a small pin to help carefully scrape the build up off the coil, but you have to have a light touch so you don't wreck the coil. Seems to be working so far, and better than just trashing them once they won't vape. I also found that you have to be careful removing the bridge, push against the ceramic area with a tooth pick then pull up on the bridge with tweezers or tiny needle nose pliers. That way you don't pull the inner workings out with the bridge. Good luck to ya.