It is not to hard locating these trays, but locating them being in a rust free condition can be quite difficult due to individuals have used them in the past and wet glasses have caused them to rust. Trays that are mint condition are extremely unusual and can cost the collector a pretty plenty, but it is well worth noting that common trays from the 1950s and even later have substantially fallen in price. During the late 1970s, there were reproductions of some of the most popular early trays reproduced by Coke, which are marked as reproductions on the back of the trays. Then again in the 1980s in honor of their 100th anniversary they also produced reproductions. Of course these are popular, but they are considerably less valuable than some of the originally produced trays. Collectors also enjoy collecting Cola Cola's famous bottles, with the early ones having the greatest value. These bottles are hand blown and are mismatched as to color, form, and even size. Earlier bottles were made with a rubber seal and the cap with a wire, but the taste was affected by the rubber so this type of top did not last long. The Coca Cola bottle shape that everyone all over the world recognizes was officially adopted in 1916. These bottles have become valued Coca Cola memorabilia no matter their age, and especially those that commemorate special events. When the introduction of aluminum cans came in the 1960's, commemorative and vintage cans also became collectibles but normally if they were unopened cans.