I went through my bins during Covid, inventoried what I had and sorted items.
Things like dash stuff together, heater parts, transfer case parts, body parts, etc. Some of the smalls / bolts got de-rusted. And then the hard decisions on what was too far gone and could be tossed/recycled.
Mainly did all that so I could find what I had when I needed things rather than pay the pricing for new and the shipping that continues to rise.
I started selling here on Classic occasionally and paying attention to the parts needed section. As ared77 says Bundling parts together is a good option rather than just selling a lens here or a bolt there...
All the other places can be a pain to deal with tire kickers, FB Marketplace, Craigslist, and eBay. Patience is required.
USPS flat rate boxes are a good option, my Wife has done eBay for a few years so I look to her for guidance at times on shipping. You can establish an account with USPS so you can print off your own label's. You just need a scale for weighing boxes, if you don't use flat rate.
Packing up items... Can be challenging once you deal with big items, like seats. Generally, I try to package items well, so they don't get beat to snot by the shipping folks, as it just seems nobody cares anymore, after all its not their item... There is a fine balance, as you want to protect, not add weight = cost. My wife saves boxes for her eBay sales, so I usually don't have to hunt for a box, just ask for permission to use as she sometimes has boxes earmarked for specific items.
Be prepared for people to ask for price help when it comes to shipping costs, hard to buy an item and have the shipping cost more than the part.
I have also had success selling parts at WH's swap meet which is in October usually, the goal is to come home with less than you came with

. Not really helpful if you live out of state.
Another option is if you are attending a Bronco event, you can advertise in advance and say pickup can be done at the event.
Hope this helps, Doug.