Don’t throw away writing projects that you put aside, that are not working, that you’re struggling with.
Instead, start a folder—either physical or on your computer–titled.
This is where you are going to keep all your manuscripts in process.
The ones that feel like they never get further than a mind dump, the ones that feel like you just can’t make progress, where you’re stuck, where your craft just doesn’t seem to be up to your vision.
Revisit the folder every few months. See if there’s something, a project that calls to you. Spend some time noodling around with it! With the benefit of distance you might see the potential, recognize where you were headed, see what it is that you were trying to say. . . .