Woadster

If you come across a man called Wadster you can be fairly sure that his ancestors were woadsters and dealt in blue dye.

As to the blue-dyeing, I think it would be certainly a very good think to get a woadster over; though you know the old books all say that the woad vat is not good for silk: I don't know why, unless perhaps that the lime is bad for it: still he might help us in setting a potash vat (Cuve-d-Inde).