It’s common practice to use a method of progress capture to hold a load.
Prusik minding pulleys are designed with extended side plates to prevent a prusik hitch from entering the sheave (wheel) of the pulley when capturing progress in a haul system.
You can also improvise a prusik minding pulley with a simple pulley and some hardware. This configuration is best used for banner rigging and should be prepared in advance.
Start by finding the correct size nut and washer. You’ll want the opening of your nut and washer to be slightly larger than the diameter of the rope.
Thread the rope through the nut, washer, and pulley before finishing with a friction hitch on the load end of the line. Clip this back to the same carabiner on the pulley.
Warning: Do not use a nut and washer to capture progress with a live load. The threads in the nut and imperfections in the washer can damage a rope.
ROPE GUERRILLA 
Why do you need the nut?
This is a great idea, but can be refined. Take a file/sandpaper and smooth off all edges on the washer, especially on the inside hole, drill another small hole in it and zip tie it to the pulley/beaner..
Excellent point/suggestion. The nut is not necessary but can help with sizing if you’re limited to things around the house. That said, fewer components is best and the keeper cord is a nice addition. Feel free to send in photos of your refined set-up and I’ll add them to the post.
Another DIY method with the additional benefit of the rope not needing to be threaded starting at the end can be found at http://blog.omcgear.com/pulleys-mountaineering/. Believe it or not Singing Rock actually use to manufacture something similar to this — https://www.youtube.com/watch?v=vP_n4Bvt5gU.