(CNN) -- Before it became a national holiday, Memorial Day was a springtime holiday observed under many different titles, but all shared the same intent: to honor the brave people who died in battle by cleaning and decorating their grave sites.
A U.S. Army soldier places flags on grave sites Thursday at Arlington National Cemetery.
During the Civil War, widows decorated Confederate and Union graves alike with wildflowers. Around the time of World War I, poppies, signifying the blood of heroes, were used for decoration.
Bring fresh-cut flowers to graves this Memorial Day, said Erik Dihle, division chief for grounds care, burial operations and ceremonial support at Arlington National Cemetery.
"What we permit in a military cemetery is rather strict. We permit only fresh flowers this time of year, not wreaths," he said.
"Often [visitors will] bring very personal items. Now, strictly speaking [those objects] may not be permitted to lay at the grave site but we will honor this family or the friend of the person buried here and allow that to stay for a period of time."
Dihle said friends of some of the younger soldiers buried in Arlington, who perhaps were casualties of the conflicts in Iraq and Afghanistan, will often leave medals at grave sites, or leave a beer for their friends who have passed on.
"Now, we're not going to leave a beer can long at a grave site, but we'll respectfully stand back, and as we come along and see a half-empty beer sitting at a headstone, we know that somebody was toasting their friend," he said. Family and friends talk about those buried at Arlington »
Jim Rich, a spokesperson for the National Cemetery Administration (part of the Department of Veteran's Affairs) also suggested fresh-cut flowers, but for a more pragmatic reason.
"It is definitely a very personal tradition to visit a loved one's grave and decorate a loved one's grave on Memorial Day. We recommend using fresh-cut flowers as opposed to artificial flowers, or anything that might be plastic. That might be dangerous if it were to be left in the grass when it was mowed at a later time," he said.
National cemeteries use a mix of staff, contractors and volunteers to maintain the premises.
"We try to maintain our national cemeteries as shrines throughout the year, but because of the number of people who are going to visit our cemeteries over the weekend, we want to make sure that they're as pristine as possible for Memorial Day," said Rich.
The week before Memorial Day, Arlington National Cemetery was swarming with people, from soldiers from the 3rd U.S. Infantry precisely placing small flags in front of more than 220,000 graves to arborist teams removing dead trees and planting new ones. Other crews were tending to flower beds, cleaning or realigning headstones as well as picking up trash on the almost one-mile-square grounds.
Large cemeteries like Arlington can expect millions of visitors throughout the year, but are ready for large crowds on national holidays. At Riverside National Cemetery in California, "more than 10,000 people generally attend the [Memorial Day] ceremony," said Rich.
Not all cemeteries are nationally funded. If your relatives or local war heroes are buried in a cemetery that is historic or does not have a staff that maintains the grounds, you may be cleaning their grave sites as a volunteer or out of duty as a family member.
But good intentions can often go a long way to destroying historic markers, as Mary Striegel, chief of the materials research program at the National Center for Preservation Technology and Training pointed out.
"We recommend against using bleach or Tilex," to clean gravestones, she said. "Bleach leaves salts in the stone that can cause deterioration down the road."
Instead, Striegel suggested using a gentle soap, or products like the biocide Prosoco or an antimicrobial cleaner like D2, which target parasites that discolor and deteriorate marble stones. In addition to safe cleansers, she recommended using a soft, vegetable scrubbing brush and plenty of water for getting the grime off historic markers.
Cleaning away overgrown grass and weeding grave sites can also be a tricky job. Striegel recommended getting down on your hands and knees and using hand clippers to trim overgrowth instead of using a weed trimmer, "because the string can chip away at the edges of the stone," she said.
She advised not to tear away clinging vines from markers, because they can take some of the stone with them. Instead she said, "cut the vine at the ground and let it die." It will release the stone as it withers away.
Also, she warned that caretakers should never use an herbicide like Roundup to tidy a grave site, because the harsh chemicals can lead to deterioration in stones.