I have this problem too - if I enjoy just a few puffs of my VG-based stuff in the evening I'll have an episode of annoying throat-clearing the next morning, even after I eat solid food. I'll have to give that menthol idea a try, I can't keep making these noises at the office every morning or someone's going to get really ...... (I'm pretty much ...... already myself). I'd appreciate any other suggestions for how to "cut" that awful morning phlegm at the back of the throat without making so much noise.
And no, cutting back on the VG in favour of some PG won't work for me, as my lungs don't seem to tolerate PG well at all - I get stinging pain in my chest after I vape PG, which is much worse than the throat thing.