Brass is soft and when potentially corrosive stuff, like salt, is placed in the bowl and not wiped clean a reaction happens and the surface of the brass is affected. Sometimes it can be almost all removed but it rather depends on how long the stuff was left in there.Almost every bowl I come across has some similar marks. There are a very few pricks in the base of the bowl. I cannot say when these scales were made.
I wish I could as I get asked all the time. There are no historical records of scales manufacture and all my research has not uncovered much information. At one time, in the very early days, scales had a verification stamp, designed to ensure they were properly calibrated, and this could be dated. When it was no longer necessary to have scales verified these stamps were discontinued. So basically it is not possible to date scales after around 1900.Also, sellers like Boots used different manufacturers at different times. Their moulds were different so the resulting scales were not the same either. Furthermore, as companies were taken over any historical records were dumped. UK couriers will not accept a PO Box address as US couriers will not deliver to one. You may be concerned that they have to be sent such a long way but I can assure you there is no need. I use large sturdy boxes and pack all the spaces so they remain rigid.
The scales are wrapped in bubble wrap and bound with cardboard and tape so they do not move about. The weights are packed separately also in bubble wrap. I will gladly provide further information or photographs. This item is in the category "Antiques\Mercantile, Trades & Factories\Scales".The seller is "stuffbyiris" and is located in this country: GB. This item can be shipped to United States, all countries in continental Asia, Mexico, Brazil, Canada.