CLARK, Philippines (AP) -- Walking along the rows of tombstones here offers a glimpse of the wars America has fought and the men and women who waged them. But most of the grave markers have been half-buried for 20 years, and there is little hope that the volcanic ash obscuring names, dates and epitaphs will be cleared any time soon. Clark Veterans Cemetery was consigned to oblivion in 1991, when Mount Pinatubo's gigantic eruption forced the U.S. to abandon the sprawling air base surrounding it. Retired U.S. soldiers, Marines and sailors volunteer to keep watch, relying on donations to try...