welding tip cleaners?

[paulm12]

from an older toolbox I got recently. Not sure of the age.

 

[Lelandwelds]

Never seen those before. Probably older than 1976 unless my local Airco just never stocked them.

Tip drills will ruin a cutting tip. Stick with Wypo tip cleaners.

 

[Private Lugnutz]

Stick with Wypo tip cleaners.

This set was with a bunch of other stuff in a homemade wooden toolbox I picked up this past weekend. I know they still sell them in the same aluminum holder (now in multiple colors), but I wonder when they stopped putting the hole sizes and the patent info on the back. I am guessing early 50's on this. It can't be earlier than 1949, which is the date of the second patent.