I had a fireplace thermocouple gone bad several weeks ago. I tried using an air can to blow debri and dust. I even purchased a metal brush to scrap the rust off but it seemed nothing was working. I then decided to purchase a new thermocouple online and install it with a step by step video to teach others. My fireplace now seems new. Product link below, Check it out!
Fireplace Thermocouple Pilot Assembly:
https://ebay.us/WB7RkA
Check out the store:
https://www.ebay.com/str/numbernyc
Check us out backstage:
/ numbernyc