If you're moving back and forth between silicone and water based formulas in the same airbrush - you MUST clean properly between formulas. The 2 formulas do NOT like each other and you'll have a gummy mess in no time.
Along the same lines, you MUST use a thinner AND a cleaner that is compatible with each formula or - once again - gummy mess.
The appropriate thinner should be on hand to help with drying in the gun. I fill up my airbrush with thinner whenever the gun has to sit for more than a couple of minutes. Problem solved.
I encourage Nurturing Force cleaner - it is one of the rare formulas that cleans water, silicone and alcohol base. A true multitask-er.
As to the water based formula.... let's just say I use OCC.