Cleenol Purple Beer Line Cleaner 5Ltr (Pack of 2)

Euroffice

Plastic. Purple beer line cleaner changes colour if the line is dirty, when it remains purple you can be confident that your line is absolutely yeast and bacteria free. The non-tainting formula won't affect the taste or smell of your beers.

Amazon

Ready To Use Long Lasting powerful blend of caustic alkalines changes colour when cleaning is complete chlorine based bleaching agent