Inspired by this post on the Revit Ideas forum, here is a new tool that will remove all Paint from your Revit model for one or more materials. Much faster than doing it one at a time!
Download the source code or installer – https://bitbucket.org/BoostYourBIM/boostyourbimterrifictools/src/master/
Support Boost Your BIM so we can make more great free tools – https://patreon.com/boostyourbim
Learn the Revit API so you can make your own great tools – https://boostyourbim.wordpress.com/learn/