Arc Raiders has heaps of random junk for you to collect, as well as more practical items like guns, shields, and keys, but they've all got their uses one way or another. The biggest sink for all these bits and bobs is undoubtedly the Expedition Project, which ARC Raiders Items overshadows even donating all the resources for workbench and Scrappy upgrades.
For the unaware, the Expeditions system is basically Arc Raiders' answer to hardcore players asking for regular account wipes. It's voluntary, unlike in Escape from Tarkov, but it'll reset pretty much all of your progression and effectively retire your character, letting you create a new raider and start from scratch every eight or so weeks. It's like prestige mode in Call of Duty. The issue many are running into is that, without a respec option, sending your character on an Expedition is the only way to reset your skill tree if you didn't go for the best skills not helped by the fact that most Mobility skills don't work how you think they do.
If you only want to respec and if you're not a hardcore player that would do it anyway, it's quite a tough ask to not only donate all these items, but to wipe most of your progression, too. At least you'll be rewarded for your efforts until your next Expedition with bonus XP gains, Scrappy materials, stash space, and even bonus skill points based on the value of the items in your stash upon departure.
The first stage of your Expedition caravan, the foundations, is simple enough, mostly requiring metal and rubber parts, which your best pal Scrappy hands out like candy. The requirements quickly escalate, though, with stage two demanding electrical components and cooling fans, stage three needing lightbulbs and other electronics, and so on.
The good news is that you can at least donate these items as you go; you don't need to drop them off in one lump sum—not that I think you'd even have the storage space to pull that off. Nevertheless, only once you've completed all five challenging stages before the first departure date in mid-December are you finally ready to send your character into the sunset. In other words, it's a long, hard road until you can reset your skill tree, sorry.
Don't get me wrong, while it's far from ideal for casual players who simply want to reset their tree, the Expedition Project is a smart approach to the controversial wipes mechanics of other extraction shooters. And you're rewarded pretty heartily for it, too. However, you have to do all this every time you go on an Expedition, which could be as often as every eight weeks if you're participating in every event. I reckon even the most devoted raiders'll get bored with cheap ARC Raiders Coins that treadmill soon enough.