In order to avoid paint scraping at wrist or ankle joints coat the joint with acrylic floor wax sealer prior to reattaching them.
 
You can usually find these under the name brands of Future or Mop ‘n Glow at your local supermarket.  It has a low viscosity so it paints on very easily.  A coat of this will create a slick surface over any paint applied to the joint, lessening the chance of scraping paint!
 
The finish will be extremely glossy so you may want to use it sparingly, only covering those areas that will be in contact with each other.
 
Likewise it can also be used to add a subtle dimension to your custom’s eyes.  Coat them with a little of this and it will create a shiny look to the eye making them look a little more realistic!
 
Also use it to coat any metallic look you have on your figure.  It’ll beef up the shine and make it glisten.
 
*CAUTION! : Do not apply a coat and then spray with a matte finish!  It can cause a chemical reaction which could cause a white paste to form on your hard work!
How do I stop paint from scraping at my wrist/ankle joints?