Don't throw it out, at least pop it on Craigslist for free and stick it at the end of your driveway for pickup.
When it comes to extra stuff laying around, I keep a small amount of as many things as possible. For instance, I keep a couple 2x4s, a couple partial sheets of plywood in a couple different thicknesses, a couple sticks of 1/2", 3/4", and 1" pvc, one pack of roofing shingle tabs, a couple sticks of 1/2", 3/4", and 1" EMT, one pound max of each of the most common nail sizes and screw sizes for home repairs and small projects. I also keep a couple each of things like pvc fittings, electrical terminal crimps, etc. That enables me to do small/medium projects or do a good job fixing pretty much any automotive or home emergency repair without having to go to any store.
If I have more than a couple of the same thing, I send it on its' way unless I have a specific or sustained use for it. Having a selection is good though, so I rarely get rid of anything if I only have one or two of them. Any parts, carbs, water pumps, etc. that have been removed from something I usually recycle unless there is a specific reason to keep them (rare). Anything larger like older small appliances, I donate or take apart and keep keep several of each type of screw the item has (for future repairs of other items), or any other small internal parts that I might want to keep or repurpose, and the rest gets recycled. Sheet stock, I keep one or two max of any I might have a use for in the future. Too many of one thing, and the likelihood of ever using the 4th or 5th sheet becomes almost zero.