Hey guys. the flue in the pic is attached to a zero-clearance fireplace thats at least 20 years old but more likely from 1993. from some quick google searches, it looks like corrosion from the inside of the flue maybe. i've heard some advice to use a steel brush on it and then use some high heat paint. i've read other advice that said just to replace the pipe. is there anything i can do to fix this and is it safe to use for now?
thanks!
thanks!