Qitzur Shulchan Arukh – 187:3-5
Anyone who finds a lost item,whether it has an [identifying] sign or whether it has no sign, if he found it in a manner in which it is usually placed down, like a tallis or axe alongside a fence, Even if there is reason to be unsure whether he placed them their intentionally or left them there, it is prohibited to touch them.
Someone who is a respected elder and he finds a lost item which is embarrassing, so that even if it were his he wouldn’t pick it up to bring it to his home because is would be embarrassing for him, he doesn’t have to busy himself with it. In any case, it is appropriate for him to act within the limit of the law and busy himself with [returning] it, even though it is not according to his honor.
Someone who finds something and does not know who lost it, whether it has a sign or whether it doesn’t have a sign, there are in these topics many distinctions between the laws, and you should ask a learned person what to do.
A lesson to take even from se’if 5’s statement that the laws are too involved for a brief guide like the Qitzur Shulchan Arukh. How much quicker we are to ask a rabbi a question of kashrus than one of proper financial behavior! Notice the warning here; these laws too have their complexities, and cultivating a habit of consulting one’s rabbi when they touch issues that are beyond our knowledge is appropriate.