Violin:

Dixieland bands seldom use violins. Its historical reason is that in the beginning of the 20th century no sound amplifiers were used in concerts and the soft sound of violins were suppressed by the other instruments. That's why violins were gradually negliged by dixieland bands. (There were some experiments with trumpet-like funnels attached to violins, but the sound was not only amplified but also distorted by it.) In the 1950's, when amplifiers appeared, some revival bands bstarted to use violins and use it even today.
As a follower of Didier Lockwood in France, Frankie Lato learned playing violin in jazz. With his virtuoso production he gives a special character to the music of Storyville Jazz Band.

Washboard:

In the 19th century this thing was used in washing. A couple ot street musicians discovered that the washboard can serve as a rhythm instrument when knocked with a thimble or a metal stick. On the streets of New Orleans it became a popular instrument. You can hear it in the music Wild Cat Rag played by Pál Háló in the menu of Jazz Bag. The specialty of the Washboard used by Storyville is that its owner has received it from Joe Muranyi who had brought it from America.