Hi everybody. I have a problem of getting rid of OEM parts when making mods. I was unable to sell them, especially on Ebay and those stuffs are still in good condition. I regret to throw them away. Any ideas?
PS: please don’t advise me not to do mods. It’s my hobby
What kind of OEM parts are you talking about?
Personally, I would be reluctant to purchase used parts on Ebay, but that’s just me.
Parts for honda?
Coil springs
Struts
Muffler
Radio
First 3 are wear items. Hard to resell
None wants stock radio
Maybe hood? Carbon fiber is cool
Stock air cleaner? Boring
Stick 'em in the basement until your car is old. You’ll suddenly see a great market for all of that stuff as the auto parts stores stop carrying what people need.
PS: I’ll never advise someone not to do mods as long as they do them properly and with safety in mind. Modding a car is half the fun. 
Yes. Since it’s a Japanese car, those stuffs may last for the entire life of the vehicle, IMO.
Almost everything, wheels, tires, calipers, swaybars, struts, springs, floor liners, air intake, navigation, headlights, tailights, interior trims, steering wheels, etc. I hesitate ro upgrade I can’t find a way to put them away.
I know it sounds kind of stupid but I can’t afford a new car. Honda & Toyota are more reliable and cheap to repair than others so I stick with them. If I buy another one in the future, this car still my daily commuter
Almost everything , except the body
I do exactly as you do. I have made quite a few mods to my cars over the years. Springs, exhaust, dampers, stabilizer bars, brakes, wheels, ect. If this is a newer car you may re-sell, keeping the parts and then putting them back on the car when you sell generally helps re-sale. Normal buyers don’t want your modifications, it scares them!
If you, like me, have no space for storing the old parts, there are very limited places to rid yourself of parts. Brake parts, springs and stabilizer bars and dampers go straight to scrap steel recycling. No one wants these parts, you won’t be able to sell them. I’ve tried. Intake parts and other soft interior parts go into the trash for the same reason. Aluminum parts are well worth taking to the scrappers for recycling.
Wheels and tires and seats sell well on Craigslist if they aren’t just horribly ugly… ECU’s and other electronics - Ebay is the only place to get a wide enough audience.
Have you thought about junkyard? It’s just come to my mind. They may have all these stuffs and we can sell them at lower price
Junkyards don’t buy parts, they sell them. They will take them from you for free tho…
More power to you if you can get a junkyard to pay for your old parts. 
I’d save the wheels as spares and take the rest to the “distribution center”… formerly called the “dump”. That was when the guys who picked up the trash were called “garbage men” and not “sanitation engineers”.
I would keep them for a while in case the mods don’t work out.
Actually, Sarge, I agree. That’s the best idea.
We all know countless stories, for example, of problems caused by prolonged use of cold air induction systems with oiled filters.
I also have felt the guilt of trashing functional old parts when making changes on a car. But, let’s face it, who in their right mind would go to the trouble of rebuilding their front suspension with my old parts? The labor is a huge investment, and I know I’d be unlikely to want to try that. Maybe if it was a restoration project on a 64 Rambler American, but not just to maintain an 8 year old Toyota.
When you decide you want to “upgrade” your car, you take on the responsibility for dealing with the old parts, and it’s unlikely anyone is going to thank you for your gift. Like @sgtrock21 suggested, keep them until you are satisfied your upgrades actually work right, then recycle them.
And, does anyone want a couple of motor scooter seat bases, dried out powdery foam padding and all? I’ve got them somewhere. Time to clear out the garage, I guess.