The finder of a thing may sell it, if it is a thing which is commonly the subject of sale, when the owner cannot with reasonable diligence be found or being found refuses upon demand to pay the lawful charges of the finder, in the following cases:
(1) when the thing is in danger of perishing or of losing the greater part of its value; or
(2) when the lawful charges of the finder amount to two-thirds of its value.