I have tried it too. I cut the filter in half down the length into two thin ones and used one half,
spread it out a bit so that it doesn't fall out. Works okay.
(Doing this I also discovered through these forums that you can pop the top of the 510 cartridge, and not only that can also
remove the middle o-ring inside. I guess they are there to stop liquid leaking back up. It surprised me how much liquid had
gathered there. So now it's all hollow and bare inside, and wow, it improves the drag when vaped this way (without the top and o-ring. Guess at home i'ts ok to leave it this way).