Hi, i also have Creality Ender 3 Pro. I have same issue about print bed. Now i’m using glass bed too. Why i need to cleaning glass bed, is because i used to sticking glue stick to glass bed before printing, and hope that the filament can stick to the glass bed. But it elave mark on the glass. So what i do is, i put some liquid soap (i use body wash), and add some water, mix it ant put into spray bottle. Then i heat up the glass bed, spray the glass bed with soap water, then scrap it with side profile of cutter. Some also directly using side profile of cutter to clean it.
Hope it helps.