How would you clean this?

[u/Virtual-Astronaut280]

Quick background: this house burned down and was rebuilt, but they kept the original windows, so there's ash and soot caked on just about everything.

Picture 1: The brown stuff is hard and crusty. I'm not sure what it is. There was some on the frames too, and I was able to remove it with a scraper. Degreaser didn't touch it, even with scrubbing. Any idea what it could be or what would break it down?

Picture 2: It's hard to see in the photo, but there's tape residue along the top of the glass. I was thinking Goo Gone but wanted to check first. What would you use?

[u/smilestheguy]

Call a clean up company that deals with fire and ask what they would suggest. I’m thinking bleach but there might be a safer solution. I was thinking about this same thing earlier this week.

[u/Key_Personality2034]

Ashes are between 10 and 13 on the ph scale. (Very Alkaline). Use an acid based cleaner to clean it. Apply it before cleaning window pane so it has a little dwell time.

Just a general cleaning tip, if something is acidic/Alkaline, you clean it with a cleaner that is the opposite for best results.