Karen--GREAT idea! Historic bricks make a wonderful artifact. After St. Mary's Cathedral burned down in 1962, the Archdiocese took used bricks that were salvaged in the demolition process and sold them as part of a fund-raiser for the new cathedral. When the Davies Symphony Hall was under construction on Van Ness Avenue circa 1979-80, bricks from the old St. Ignatius Church & College were unearthed and saved by collectors. Also in 1979-80, I remember seeing pedestrians at Stockton & Geary rescuing old bricks from the City of Paris demolition site. I'm willing to bet that some old City Hall bricks, salvaged over 100 years ago, are still lurking in boxes that are being passed down among some long-time SF families.