Last thing probably you want to hear as it would involve more money (and is a bit gross)... tongue scraper (told you, gross). Morning and night stainless steel one from DR. Tungs. I will also, if able, do a quick brush with just water. Both help me at least when flavor drops off.
Another thing is that taste has almost as much to do with scent as it does with taste buds. When my allergies get bad a quick sinus rinse helps me a bit. Cooking is my first hobby/work. So taste and scent have always been important for me and I noticed a bit of cross over with vaping.
As always your milage may vary.
Actually, what flavors have you been using? Since I have been using a 'fresh squeezed orange' the last couple of days when I do pull from my 'tobacco, nutty, carmel, is that a bit of cocoa' flavor I notice more from the latter. The fresh squeezed composition seems to not gunk up my palate as some other liquids do.
Any one else have juices do this?
Three plus years in and just finding a couple keepers in liquid land.
RC Hagy