Here are some links on how many pre-1933 U.S. gold coins were saved and the man who helped save these coins. http://www.numismaster.com/ta/numis/Article.jsp?ArticleId=13636 https://en.wikipedia.org/wiki/William_H._Woodin
Large numbers of the coins were also kept overseas in banks, etc. Especially in European countries and thus avoided the recall and melt.
A lot of coins were also just not turned in and people kelp them anyways. People buried them hide them in buildings, attics, craw spaces, basements and even on other people's property.
How happy would you be to have your life savings stolen by the pols and turned into green TP? I recently found a "mason jar bank" w/detector. Only "common date" morgans tho'-no yeller ones yet....
Two other good places I could think of for hiding would have been under steps in old houses or floor boards. Maybe even hollow spaces around windows (random thought)?
Or a trick that was done in Italy years ago. Cut a hole in one of your interior walls, insert gold or silver coins. Plaster over hole, repaint to match. Whitey Boldger of Boston crime gang did a variation of this idea where he was hiding out in Calif. He had cash hidden behind the sheet rock in one of his rooms.
