never use Windex or anything with amonia.

I have been using standard foam spray glass cleaner on glass then I come back and wipe down with acetone to remove any and all impurities.
I have vinyl large and small on for 2+ years and still looks good 

To remove adhesive, I use wd40 and a plastic razor blade or small pink scraper.
For my app fluid, I use 1 part alcohol (91%), two parts water and three drops of cheap baby shampoo.  I bought a little trial size and have been using that same bottle for two years...

I use a microfiber cloth to clean the glass (no lint).

I try not to use wet application unless I absolutely have to.  When I do, I usually hit the decal (with the app tape still on it) with a hair dryer to help speed up the drying, then I spray down the app tape, leave it for a minute and pull the tape off.

I'll have to add the vanilla.  Even I would enjoy having something that smells better than the alcohol.
Since extracts are alcohol based, it shouldn't matter.

Heck, you can add any artifical extract......almond, lemon, vanilla..........

Great idea!!!