Come on folks - this is Switzerland. Everything has an ordered solution.
Go to any Post Office and ask for a Vignette removal kit for a few francs (seriously). It consists of a couple of wrapped moist wipes and a small scraper (smaller version of a glass ceramic hob cleaner).
Now armed with this info. you could indeed make your own kit and save a few francs - unless the moist wipes have a special formula to counter the specific glue used.
Or, like me, you stuck it (them) on in a hurry, over the black tinted adhesive anti-glare strip on the top of the windscreen, so can't use the scraper (doh!).

Yep, that's the solution - 6 CHF and done.

I just go to my usual garage and the guys change it for me. Thumbs up for fantastic Swiss service!

In case that doesn't work for you, try this:

Coop diy store, 5CHF 3 wipes - so as long as you hide the wipes in your passenger dash you wont even have to go and look for a kit for the next few years!

I brought the Vignette at a Post Office. It came with a blade and a pen type eraser to remove the residual glue. It costed 6.9 CHF. Removing the residual glue with the pen type eraser wasn't so elegant and took considerable time to get the glue on the glass removed.

After I removed the Vignette using the kit, I just put a little bit of spit onto the glue, after the using pen and wipe, then continued with a few more swipes of the wipe and it came off easily.

For the last few years I have used the hairdryer and white spirit method with no problems. Once the old one is heated up it peels off very easily and the white spirit deals with the glue residue perfectly. A few minutes only.