I wrote this for some of my Leo users. Please take this with a grain of salt:
The atomizer of the Leo can also be cleaned. You may notice after several weeks that the taste isn't right with the atomizer or vapor production changes, or that the 'hit' becomes too hot. This is because layers of different flavored juice have wet, dried, wet again, dried again on the electronic atomizer components. With the heating/cooling action those juices may have caked on there pretty good. You may also notice the performance isn't the same. Cleaning is simple:
1 remove atomizer from the battery.
2 run atomizer under very hot water for a few minutes. You can even soak the atomizer in alcohol for a couple hours. If using alcohol, rinse with hot water after soaking.
3 blow out all the water you can from the atomizer. I like to use an air compressor set to 80PSI. If just blowing out dry with your mouth it is recommended to let the atomizer dry upside down over night. Using an air compressor speeds all that up and gets out 95% of the water trapped inside.
4. Once dried (or air compressored), prime the atomizer with 2-3 drops of a light flavored ecig juice. Try not to use a heavy flavor or thick VG juice. Plain PG is the best. Drip those 2-3 drops right onto the atomizer.
5 dry burn the juice you dripped inside. Do this by attaching the atomizer onto the battery without a cartridge, and activate the battery so as to heat up the elements inside the atomizer. Do this until the coil inside the atomizer turns a glowing orange, then STOP. Let cool (blow out vapor). Repeat the process until most of the sizzling and popping sounds stop and it is a nice, smooth sizzing. The popping sounds is the water droplets superheating and exploding. When the popping almost stops and it becomes that nice, low pitch sizzle it is ready.
6 at this time insert your 302/801 cartridge and begin to vape. DO NOT worry if the vapor it produces is minimal at first. This is normal and the vapor production will go back to normal within 30 minutes of use. Letting the atomizer dry completely over night usually avoids this and the atomizer goes right into vaping nicely. Having a second atomizer to use while the first is drying, is helpful but not necessary if you time it right to dry while you're sleeping.
