Try this, it works for me. Do everything you're doing to clean the threads and screws. My final cleaning is always acetone.
Use your blue loctite on the screw threads. I also get Gorilla glue construction adhesive. I spread it on the top part of the screw just under the head.
The loctite adheres the screw to the threads, the glue secures the screw to the body of the dot. Take a Q-tip and remove the excess glue around the screw after torquing.
The screws are easily removed.