Shelton Historical Society shares stamps once offered by grocery store

From the Shelton History Center's Facebook post:

These Macdonald Plaid Stamps from 1968 were offered by the A&P grocery store in Shelton. The Shelton store opened at 475 Howe Ave. in 1942. The store eventually relocated to River Road in the late 1960s and closed in the early 1970s. 
The building is now a self-storage company. 
Do you remember trading stamps?