Is it OK to use Pathex if it has turned brown?

Pathex concentrated solution ranges from golden brown to medium brown. The diluted use solution should be nearly colorless to light tan. Diluted solution that has turned medium to dark brown may be ineffective and should be discarded. Possible reasons for dark color include: outdated product (check expiration date); diluted solution that exceeds the 60 day use life; exposure to direct sunlight; or exposure to excessive heat during shipping or storage.