Visitors leave 45 pounds of offerings from Halemaumau Crater each week, including flowers, bottles, money, incense, candles and crystals, park rangers say.

But food offerings are the most problematic, they say.

"The accumulation of rotting food and foliage attracts rats, flies, ants and cockroaches," a park statement said.

One ranger recently found a whole, cooked piglet replete with a papaya, orange and apple in a cardboard box, the park service said.

The rotting offerings pose a hazard to the endangered nene goose, the state bird endemic to the Islands, the park service said.

People also burn fake money which in Chinese culture is meant to aid people in the afterlife. Such fires are illegal, the park statement said.

Park Superintendent Cindy Orlando said the park must preserve the summit area, which has special significance in Hawaiian culture.

Some Hawaiians believe lava is the physical representation of the fire goddess Pele, making the volcano summit sacred.

"We look to our partners and local communities to assist us in communicating the value of resource protection and cultural sensitivity," Orlando said.