Canada balsam, as it does not decolourise the specimen.    From Wordnik.com.  [The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged.] Reference

Stain deeply, if using a single stain, as the subsequent processes decolourise.    From Wordnik.com.  [The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged.] Reference

Well-formed, dense cell membranes, which renders them extremely difficult to stain, but when once stained equally difficult to decolourise.    From Wordnik.com.  [The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged.] Reference

Or magenta treated with a bleaching-agent in just sufficient quantity to decolourise it is invisible when used for writing.    From Wordnik.com.  [The Poisoned Pen] Reference

Wash in water, decolourise if necessary.    From Wordnik.com.  [The Elements of Bacteriological Technique A Laboratory Guide for Medical, Dental, and Technical Students. Second Edition Rewritten and Enlarged.] Reference