u/Just_Tyler231

Was cleaning my linear drain (hair tends to get caught) and noticed this discoloration not coming off. Instead a paper like substance started to peel off and the black top layer was getting scraped off since I was using a brush.

Is this something I should try to remove all of then replace? The width of the channel is quite narrow so I’m not entirely sure how to get it cleaned up and replaced or what it even could be.

Any help appreciated thanks!