I would use Krylon Triple Thick.
Cut little pieces of card to go over clear score windows and put small weight on each. Clean them first obviously!
Lots of videos how to apply.
Mustn't be too cold or hot - ideally 55 - 75 degrees.
If done well, it will keep the glass from deteriorating for next 30 plus years.
Only thing to be wary of is after doing this, don't let glass be stored in very cold conditions as the ink and triple thick can react.
Way better than using mylar which goes yellow over time.