A company that runs lots in the English cities of Leeds and Manchester is temporarily letting drivers pay with the dark brown seeds that fall from horse chestnut trees each autumn.
Town Centre Car Parks is accepting horse chestnuts for parking time at a rate of 20 pence (32 cents) apiece.
So far it has collected about 1,500 of the nuts, known as conkers after the traditional game in which children take turns trying to smash them.
The week-long "Bonkers for Conkers" campaign is due to end Sunday but may be extended.
The firm said Thursday it plans to sponsor a forest to help offset carbon emissions. It hasn't decided what to do with the conkers.
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