For Inquiries about our products or pricelist, please leave your email to us and wij will be in touch within 24 hours. Inquiry For Pricelist Middel color will be restored back to white after organic binder combustion. Middel should be heat treated first before use in a smoke-prohibitive environment. Zachte https://blogs.cornell.edu/advancedrevenuemanagement12/2012/03/28/department-store-industry/comment-page-4846/