I just spilt hot cocoa on very expensive velvet

[bydaytisbright]

How do I get it off?

How much have you spilt? Try to blot it up - do not, whatever you do, rub it. Is it cotton velvet or made of silk or viscose?

silk velvet

I just sprayed a load of vanish on it (before I posted). was that a bad idea?

Probably - silk is very delicate and I think it says on the bottle not to use Vanish, though I may be wrong. The main thing with any spill is to soak up as much of it as you can before you then try to clean it.