Depends how thick the layer for what works best. often a combo is needed to speed it along. If it is really light, some form of light acid like vinegar and scrubbing may get it but if it is thick enough to be scraped with a fingernail, I go for quicker than scrubbing. One of the cheap,handy tools is a razor blade scraper like designed to remove paint from windows after painting. about three dollars from most any hardware and they hold a single edge razor blade to make it safe as well as keep it flat against the glass to avoid scratches. Once the big stuff is off, I then go for the vinegar and scrubbing.
This is one form that I like as it lets the blade retract to store safer. I don't like to see my own blood!
WARNING! Keep it back from the corner silicone to avoid lifting it. Run the blade parallel to the seam not toward it!
Last edited by PlantedRich; 01-29-2019 at 03:23 AM.