Don't put it in the washing machine, busc and bones could be damaged.

Wash it gently in tepid water with a nonabrasive soap . You can use a soft brush...

Take care when you brush the fragile fabric such as silk or taffeta...Don't wet it too much and don't twist it....

Let it dry flat. if you are in a hurry you can use a hair dryer but on the coldest position of course...

On the other hand to clean the lacing ribbon, you can machine-wash it and iron it to make it flat...