I am finishing my second week with a eGo-T atty and it is going strong...I have done nothing to it--I'm using 70/30 pg/vg from backwoods brew. Another tank atty I was vaping vaperite 50/50 and it clogged up in 2 days. I washed it out with hot distilled water using a turkey baster,blew it out, and let it dry for 24hrs and it worked great.
I've been using 85% aqueous glycerin (VG + 15% deonised/distilled water), 14% PG 1% nicotine (I don't use any flavor for safety reasons) and it seems to work well if you do this:
1) remove little membrane from the cap of the tank (tank internal side), I didn't need to make the hole larger, just remove the membrane, I've heard this tip in a youtube video. I've no idea if 100% PG eliquid leaks after this, but my eliquid 85% aqueous glycerin doesn't leak.
2) I don't fill the tank 100%, I fill it 80% or so to leave some air. The first time I tried 85% aqueous glycerin it looked like it worked ok even without removing the membrane at point 1 because I filled only 50% of the tank or less (to try it out). But then I tried a 100% fill and I run out of eliquid in the atomizer pretty fast. I didn't yet try again a 100% fill of the tank but 80% seems to work perfectly after removing the membrane (I doubt 80% would have worked with the membrane and the hole of the tank not entirely clear).
I'll be trying 99% aqueous glycerin and 1% nicotine soon and I hope it will work as well. After 1 week of 100% PG or 70% PG, it turns out I don't really like PG so I want to get rid of it (again, I used 99% VG eliquid before I purchased the tank system for almost an year and had zero problems with it). But reducing PG to 14% of the eliquid seems to be quite decent already.
I blowed air on the battery side of the atomizer only once so far, it don't do every time but I think it's good idea once in a while to remove most eliquid in the atomizer, especially with VG.