Middletown Plate Company Quadruple Hard White Metal Butter Dish - 1800's

This is a beautiful embossed butter dish made by the "Middletown Plate Co."  It has "52" on the bottom and a picture of a scale.  The top and bottom are in good condition - the top has 3 nitches, but not noticeable until you feel them from the inside.  The butter tray on the inside is noticeably worn.  I have not cleaned it for fear I would damage it.  The top has large floral patterns and a floral etching.  It has an attached butter knife holder.  Would like to know the value of this piece. 

Poor