I have quite a few Mercury Dimes, some look uncirculated, dated from 1941-1945 s One set in particular is in a black plastic case with plastic screws at 6 points, and the coins look to be in better shape than some of my other circulated Mercury dimes... Were these coins put in here at some sort of store? Or are these aftermarket cases that collectors put their own dimes in? Thank you in advance
That holder was made by a private company called Capital Plastics. They are sold without coins so collectors can assemble their own sets. http://www.capitalplastics.com/
Capital Plastics holders were very popular through the late 1970s and many late-date Merc short sets (such as yours) as well as War nickel sets survive to this day with coins in them.
That is exactly what I have in my collection. 4 Mercury dime sets, 4 war nickel sets and set that says U.S war time coins...
I have always liked the Capital plastics holders. You can find empty holders on eBay from single coin holders, year /proof set holders, type sets, even complete set holders (expensive)
Grainger has them, here is a link. http://www.grainger.com/Grainger/ww...le-_-TPN+-+Brand-_-Grainger-_-granger+catalog