Extracted from post by “dibw29” Great War forum http://1914-1918.invisionzone.com/forums/index.php?showtopic=70163&st=25
The stamped zinc tin which was the WW1-style container for Blanco; replacement blocks came in paper wrappers. The style of the compressed block was also different, being pretty rough-and-ready with a deep well in the centre and the name of the company moulded round the raised edge. From my experience the safest bets for WW1 authenticity are either the plain “Khaki Blanco” (comes out a similar colour to new webbing, but slightly yellower) or “Web Blanco” (khaki green, but a different shade to the No. 97 and nothing like the dark olive KG 3 of late WW2 vintage). Picture below shows- top right, embossed zinc tin; bottom right, “Web Blanco” (not guaranteed – it is marked the same as Khaki Blanco, but is a khaki green shade as described in Pickering’s 1917 advert); bottom left, “Khaki Blanco” block; top left, “Khaki Blanco” replacement in un-opened wrapper (note that on these wrappers there is no shade number – it is simply “Pickering’s Khaki Blanco”).
The other type of equipment cleaner which I have used on webbing is the Mill’s Eqpt Company’s own “official” web cleaner, which is slightly contentious: some people are certain it is WW1 period, others that it is ’20s or later – I can’t find any evidence either way. Colour is a very neutral khaki drab/green. The container is on the bottom right of this picture.