#7 and #81 are both non-abrasive polishes and perform the same function. #7 tends to work better and apply and remove easier from single-stage paints, while #81 tends to work better and apply and remove easier from clear coat paints.
#7 Show Car Glaze came out in either the late 1920's, or the very early 1930's.
After claying, and then cleaning your paint, (if these steps are needed), apply a polish, such as #7 or #81 and then apply a wax or paint protectant over the polish.
Here is a very rare and early 1/2 gallon jug of Sealer and Reseal Glaze.
Note: Bottles with Mirror Bright were manufactured before World War II, and bottles with Mirror Glaze were manufactured after World War II
Of course, I collect old Meguiar's bottles so if anyone has any and would like to see their old bottle go to a good home and growing collection, please contact me.