Kate, I'm glad you brought this up. First of all, I'm not totally satisfied with any of the materials recommended as cart material replacement in the forums. Heck, I'm not even happy with the original material in our carts. Whatever that material is...
That's why I've taken it upon myself to design a completely new dispensing system that could be used to replace all of these wicks/fillers in various cart models. The exception to the rule would be those that have the atomizer and wick contained in one component. This new system will be extremely sanitary, fire proof, melt proof, fray proof, etc. It will be somewhat expensive to manufacture compared to what we're used to in OEM cart fillers but it should last a very long time and of course be reusable via a simple rinse with warm water.
I can't really go into much more detail yet because at this point it's just on paper. Within the next few weeks I should be ready for a few 'beta' testers. Btw, what's a beta tester called when it comes to testing hardware as opposed to software? Guinea pigs? Don't fret though - there should be no safety issues to concern anyone with.
If it all works out to what my schematics suggest this new system could even convert the most devout drippers back to using carts. Wouldn't it just be heaven to have a happy medium between cart topping and dripping via a built in mechanism without all the hassle? Not to mention less stress on the atomizer while holding liquid that is dispensed consistently till the last drop.