In my CCF (Army) days, ('57-'60) we used "Webbing renovator", which was like a khaki boot polish. Put on with a brush, polished with another brush, and then buffed with a soft cloth., With care a belt could be worn a couple of times, but then it would start to flake and had to be redone. Didn't use blanco until I joined the R.A.F. Blue for regular wear, white for ceremonial parades.