In reply to Iamgregp:
To be clear I wasn't exactly being serious, I've smeared on slate dozens of times...with varying degrees of success!
To be honest my favourite Slate shoes are either a worn in pair of Miura VS or Boostics, they edge better (for me atleast) once the 'new' edge has been worn down, kinda like when the shoes have 50% of their life left.
By this point the shoes should have softened up enough to smear, but still edge really well without rolling off matchstick width holds.