Some are yellow...others purple....like the Pepper & Miles ones that he and Sjarrell are iso.
Riverside=red
Prestige=purple
Contemporary=yellow
Green = Fantasy
Actually, Fantasy=blue (at least in my collection, e.g., Brubeck--Jazz at Oberlin, Guaraldi--Jazz Impressions of Black Orpheus)
Jazzland=orange
Pablo=lighter (than Contemporary) yellow
Now that we've cracked the color code, are you sure you really wanna get rid of 'em?
Next is the refresher course on the various JRVG OBI colors.