Leather deglazer is a chemical combination that is used to prepare leather for dyeing. Processed leathers, or even finished leather goods, often come with protective finishes on them. Deglazer, once applied to the leather, helps strip away the existing finish and any additional residues or chemicals underneath it.
With previous finishes removed, the leather is ready to be dyed a different color, or have a different finish applied. Deglazers are usually highly toxic and require outdoor ventilation for safe use. They are also temperature sensitive, and should be used within the temperature range recommended on any specific deglazer you’re using.