The value of an old washboard depends on its age, type, features, material and condition.
There's an 1850 vintage washboard that sold for $200 in 1975. However, today's old washboards that show up on the market sporadically have a more modest value - priced from less than $30.00.
For a "family size Columbus washboard 2062", you can check on the actual prices here.
From the start of the Columbus Washboard Company (1895) until 1930, the only washboard produced and sold was the "Bear Easy". The Brass brand washboards were introduced in 1931-1938, and actually, the brass style is one of five styles the company made that continued to be manufactured into the 1980s.
So your "Brass" brand washboard may have been made anytime between the 1930's and 1980's, consequently affecting its value.
Vintage washboards have become collectible as people like to use them for decoration. They are also sought after by restaurants looking to create a country ambiance.
While many people use local antique shops or collectible dealers to find out the value of old and/or unique items, it's usually best to use a certified appraiser who's accredited and meets professional and ethical standards.
Find expert advice on determining the value of your old stuff, featured at Huffington Post.