I don’t know exactly what year this costume is from, but it’s lovely! It’s a Walt Disney licensed, Ben Cooper Inc. Masquerade Costumes costume, still in the box!

Style: Minnie Mouse. Size: B (8-10). No. 217.

There’s cloth on the Minnie Mouse mask! 

Style, size, and number of Ben Cooper Masquerade costume. 

Life of the Party! 

Back of the box. 

Ben Cooper | Spotlite | Masquerade Costumes. The costume is sold as Minnie Mouse, but honestly the mask is just Mickey. Maybe a bow would help? Did it come with a bow?

The Ben Cooper Walt Disney costume itself is also Mickey and Minnie mouse, so my guess is they just used this costume for both.

Ah yes, even into the 1980s boxed costumes being flame resistant was a highly advertised thing. And I guess for good reason.