If in doubt keep it

I take everything I find at the beach home with me, as long as I can carry it off the beach because sometimes you never know what you have found until you become an experienced beach hunter.
I say experienced because over the years you become familiar with a wide variety of objects  recovered at the beach which’s makes them easier to identify and helps prevent you from discarding something potentially valuable 
Many moons ago I was into bottle and clay pipe digging along tidal river banks back in England, I still scour river banks when the opportunity arises. 
I would recover all kinds of interesting  finds scouring tidal river banks, usually taking bags of stuff home until I had a chance to clean and identify what I had found using my “ Twin optical” scanners. 
Everything from pottery chicken eggs and victorian glass christmas lights to boars tusks and fossils, you name it my dear old mums kitchen sink saw it lol
I remember stinking out the kitchen many a time removing corks from old bottles that were encased in river mud for three or four hundred years. 
One of the great things about the hobby of metal detecting is you never know what you are going to return home with, it could be a find of a lifetime if you are patient, persistent and lucky.
A ring encrusted and scratched up that at first looks to be junk, could turn out to be a bobby dazzler platinum or gold ring when cleaned up.
A blackened disc shaped object could turn out to be an old silver treasure coin after cleaning, you just never know until you gain experience at identifying objects recovered at the beach.
That goes for inland sites too, I have a really cool dinosaur egg I found while hiking in a western desert, yup the lucky horse shoe up my butt works in the desert too lol 
I believe because we spend so much time looking down at the ground spotting things that stand out becomes second nature.
A word to the wise if you look at a metal detector VDI screen instead of the ground you are moving over. 
Bag and tag anything unusual you pick up at the beach until you are able to identify what the mystery object it, another good thing about metal detecting is you are learning all the time. 
I class myself as quite knowledgable when it comes to identifying old shipwreck coins, jewelry and artifacts, if I do not know what something is I eventually find out and learn something new in the process.
If the beach conditions are bad or you cannot get to the beach, get stuck into some research on the stuff you are likely to find at your local beaches.
Shipwreck or maritime museums and exhibits are excellent places to check out possible future finds, perhaps you will recognize something you have found already.
Remember take your finds home just in case you make the mistake of leaving something good for another beach hunter who does recognize what you decided to leave behind.