i built a warehouse with rooms sorted by biomes, and also for weapons and trophies, etc. if i fill 2 entire reinforced chests with resources, i stop collecting them until i need to refill. that way i always have things on hand. especially for later updates who knows what will be required to make new items or gear. if i do want to get rid of things, my home base if on an island and i just throw my junk into the ocean

only useless stuff later in game are : throphies , bones and leather scrap ( unless u wanna make flags , the only thing that use them a lot )
The rest of have their good use ( dwarf eyes for portals and future food , resine for fuel ... )

You have to be host for dev commands. Throw items on ground and use "removedrops" command to remove all item-drops in the area.

Source: https://www.ign.com/wikis/valheim/Cheats_and_Codes_List_(Console_Commands)

It sort of depends where you are at in the game, and certain habits that you have.

Among the list of things that I had way more than I could ever use:
Greydwarf eyes, bones, troll leather, trophies, beech seeds, pine cones.

Those are the sort of unwanted things that I would pick up passively in my travels. Keep two or three stacks maximum. The important thing is to keep your storage organised logically. It helps your memory out a lot when you are far away from home and trying to figure out what is most worth keeping.

To get rid of items simply toss them outside the 20m radius of work benches and they will despawn within a few days.
To get them to despawn quicker, toss them into water that is at least 2m deep.

I toss them into the deeper area of the Oceon outside and away fro, my base perimeter if I dont see any sparkles from them I know its far enough away.
Items on the ground have a sparkle like effect as if to say ntoice it lies here.

Things to keep is a small list.
- constantly consumed stuff: rocks, wood, meat, arrow components etc
- at least one second-best or if wealthy, duplicated armor set and weapons for corpse runs into bad areas.
- hard to get stuff, mostly refined ore, or excess chitin that would be a pain if you suddenly needed some.

what does that leave? trophies, unused or lightly used consumables (dwarf eyes, resin, skins, low tier stuff)

I am a packrat and we have near infinite storage. That said I use a 'darwin' approach to what makes it back home. Hmm, found lox meat, but have grey dwarf eyes in my bag already... toss the eyes. Hmm, killed a sea monster but have coins... toss the coins... etc.

Main thing I toss are those stupid trophies. After you get a stack of each I drop them as soon as I get them. As above, if I'm a long way from home with a filling inventory, a critical review is necessary. First goes rock, then wood, etc.

Before I started this, I had a complete chest of deer trophies.

There's no convenient way to destroy unwanted items.
On a previous server, I dug a pit outside workbench radius and tossed unwanted things there, however lag became an issue eventually.
You could take them out to ocean to dispose of them, but could you really be taxed? I know I couldn't.
I have thought about making a portal to a storage room out of the way with nothing but boxes of hides, bones and heads.

Just throw them somewhere outside the radius of a workbench and they'll despawn eventually.

Though I find the best way to not end up with tons of junk is to not pick up everything you see. I keep one stack of each material at max (except building, food materials etc.) because the probability of me needing more than 50 leather scraps is highly unlikely. Trophies, I only keep one of each just for the sake of collecting them.

Set up a portal by the water on a rock far away from anything. Name the portal "Dump". Use your travel portal to link to it whenever you want to get rid of stuff.

Well that is what a friend of mine does. Personally I don't know what the devs may add so I am loath to throw away things... once I have too much of something I just avoid picking it up to begin with.. anything I end up bringing back to base gets stored.

As I progress through the biomes and make more bases my first base ends up being the deep storage of stuff and I take everything there I don't use currently.