Marble (toy) conventions. Additionally, many glass artisans produce art marbles for the collectors' market only, with some selling for thousands of dollars. Marbles are made using many techniques. They can be categorized into two general types: hand-made and machine-made. Marbles were originally made by hand. Stone or ivory marbles can be fashioned by grinding. Clay, pottery, ceramic, or porcelain marbles can be made by rolling the material into a ball, and then letting dry, or firing, and then can be left natural, painted, or glazed. Clay marbles, also known as "crock marbles" or "commies" ("common"), are made of slightly porous clay, traditionally
Elgin Marbles running out of ammunition, in order to prevent damage to the Acropolis. Fry had previously written a blog post along much the same lines in December 2011 entitled "A Modest Proposal", signing off with "It's time we lost our marbles". A YouGov poll in 2014 suggested that more British people (37%) supported the marbles' restoration to Greece than opposed it (23%). In older polls, Ipsos MORI asked in 1998, "If there were a referendum on whether or not the Elgin Marbles should be returned to Greece, how would you vote?" This returned these values from the British general adult population: