California Code, Civil Code - CIV § 2078

One who officiously, and without the consent of the real or apparent owner of a thing, takes it into his possession for the purpose of rendering a service about it, must complete such service, and use ordinary care, diligence, and reasonable skill about the same. He is not entitled to any compensation for his service or expenses, except that he may deduct actual and necessary expenses incurred by him about such service from any profits which his service has caused the thing to acquire for its owner, and must account to the owner for the residue.