I know I just showed you my recovered design wall. Just before I found the new covering for it, I came across this gadget for cleaning it.
This is what the other side looks like.
This is the easiest thing I’ve found for removing threads. Here is a before.
And after!
You can see below what just a few swipes did.
Then you just pull off the threads and throw them away! I’ve ne er found anything that worked this well.
I found this little gadget for a dollar at a discount store. But I found the same thing as part of this set on Amazon (no affiliation).
I hope you find this helpful. Have a great day!
KatyQuilts 
That looks amazing! Have you tried it on any other surfaces?
I wonder if you could put a strip of adhesive velcro on a handle and use it to remove the threads. I once stuck a velcro hair roller on a small roller type paint brush and used it to pick up thread off the floor. I had a long handle on it and could get under tables and chairs.