I was sitting there flooding them after only maybe 10 drips and I couldn't figure out why. then I remembered someone mentioning holding them at a 45 degree angle. Then it hit me! EUREKA! By doing it this way, all the juice is going into the filler and not straight down the tube! If it goes down the tube, then it just runs out and gets clogged up really quick. But if you hold it at an angle if just goes into the filler mostly with no clogging. I think I destroyed a few of these because of that. I actually dripped around 30 drops into one tonight by doing this without any mess. So, if you are dripping directly into a carto such as the Boge 510, use that advice! It will save you some money!