Groove placed around windows (most commonly car windows) as a seal
A glass run channel is a groove, normally made of rubber or plastic, that is found around windows (most commonly car windows).[1][2][3] The primary purpose of a glass run channel is to provide a seal for the window.
Cleaning
Due to the channel's narrowness, glass runs can be difficult to clean (or free from small obstructions like glass chips) without the use of a specialised cleaner.[4]