Is there a way to archive projects and tasks that do not belong to me?

Ah, I see!

I’m afraid this might be beyond the scope of something easily addressible in a Forum, but here’s a quick take:

Perhaps if you email support@asana.com from your Admin email address you could request them to make you a “Project Admin” for all those projects that you want to archive (assuming you are only an Editor now and thus lack the rights to archive the project).

For a project with tens of thousands of tasks, one option is what I think you’re suggesting: Age off the unneeded tasks so you turn your project into a current-only project. That’s what I suggest here:

So I do think that’s a valid way to do things, but you can only multi-select 50 tasks at a time for such aging. Given the tens of thousands to do, maybe consider making the existing project the aging/archive project and create a new, current, evergreen project, and multi-home only the current tasks there (assuming that’s only a few hundred, not tens of thousands).

There’s probably more, but perhaps that offers a start.

Thanks,

Larry