An efficient and safe shop has nothing on the floor but inventory that is immediately needed and the tools necessary to process it. Anything else gets in the way and slows the process down while increasing the chance of quality problems (stale inventory) and in some circumstances it makes the shop a dangerous place to be. A Scrum Board is absolutely no different. The only work on the board should be work that is actionable. Everything else is clutter. All work on the board has to have true meaning and purpose to what you are delivering, it isn’t a repository for to do lists, or might do someday backlog, all of that is noise. Get it off the board. You won’t be able to see the forest for the trees to manage your Scrum.