Pun intended, because there are 2 tips on each little bottle of Mayco's Designer Liners.
Drying out is a major thing to avoid with little tips. If I leave my Designer Liners (DL's from now on) sitting around for a month, they usually get dried glaze in the tip.
To avoid that I try by leaving the little bottle upside down, as well as keeping it inside the original plastic bag. If that fails I will remove the metal tip from the plastic tip, push the pin in and out a few times, then just submerge it in water and use a brush to get all the dried glaze out. ALL is important, because dry glaze will just wait till you're in the middle of something beautiful to clog the tip back up. And inside the plastic top there may also be dried glaze, which will respond to the same water technique.
All this before even using it...or at least the second time. The first time it usually isn't dried out, somehow.
I also want to thank the Mayco demonstration guy that came last year to Highwater and showed me and some friends how to use the DL's.
These little bottles create air bubbles...so keeping them shaken upside down is a great idea. Maybe they'll eventually make the bottles so they stand on their heads, but I just keep shaking mine upside down, to get the glaze into the tip, and the air bubbles up in the bottom of the bottle when in dispensing position.
You need to start the glaze coming out by making dots and lines on a paper towel or a piece of something without any grit to get into that little hole. Squeeze gently as you pull it towards you, and you will make lines. Or squeeze and tap gently on the surface and you get dots.
Avoid letting gritty things get sucked back into the nozzle. This means clay, especially. And glaze also. So I've found glazing on bisque-ware gives the least amount of grit to be picked back up by the nozzle as I apply lines. It doesn't keep it from happening completely, (even after sponging off the surface dust) so a frequent cleaning with sponge, a drop of water, and quickly making dots on my test surface will clear the tip. Also using that wonderful pin, which I keep in the sponge so I don't lose it (again.)
When the lines start to look diminished, it's time to clean the tip...starting with just tapping it on my practice surface. This must happen every couple of minutes, but I haven't been able to get away from it. I'm still squeezing at the same pressure, but less is coming out.
If you should get a blob on your work, or you sneeze and your line goes off in the wrong area...just let it dry, but not too long, and with a fine knife edge, scrape off the wrong place and you're ready to put the correct line on. However, remember how soft that bisque-ware is, and don't scrape too much.
I may have cracks in my little spirit house, but the bottom can be signed with Designer Liner. It won't stick to the shelf in the glaze kiln!