Best way to profit if you own 40+ stash tabs?

The title says it all.

Uh I dont think the title does say it all...should probably put some more detail into it.

Store every junk ilvl 60 rares for chaos?

I, being an owner of only 10 stash tabs, have it set up rather efficient, for owning so little. I could almost see no use of owning more than 20, personally. If i were you i would use The procurement program and see what you can and cant sell. I never hold onto quest gems unless they are the more in demand support gems or aura gem and try not to keep more than 2-3 at a time for myself. If i had 40 stash tabs 5-10 of them would be for base crafting items and 5links ive found along the way. maybe 5 for uniques ( i keep 2 now and when they fill up with "junk " uniques i spam trade chat for buy 3 uniques for 2 chaos , i sell out rather quickly , as long as they are still useful.
I would also keep 2 stash tabs of junk rares for chaos recipe... Label your stash tabs with selling prices to keep it organized ( like 1c ,3c , 5 c 10c exa and so on....
I really wish i could help you further but never being in your position i dont honestly know what to tell you other than jewelery and belts sell better than anything.... body armours are a hard sell even with dual/triple resists and life.... ES chest sell decent with dual resists and 450+ ES.

TLDR
Prioritize what can and cant sell and fill your stash with these items... along with most uniques, as someone could use them somewhere.

Edit: Advertise anywhere you can _ in your Description in friends list and in your signature for profile, you would be surprised how many people message you from this. TRY TO PUT BUYOUTS ON EVERYTHING.

I have about ~50 and pretty much cleaned out my Domination tabs just this week (sold to vendor). I originally had kept a lot of stuff so I could gear up other characters, and really didn't know what I might need (or even partly what's good to keep), but now that I know what styles I like, what makes items good, and what works for me (and higher level maps are like), I got rid of the junk.

As for how to profit from the stash tabs, yeah, as was mentioned, you can keep stuff in them for the chaos recipe, or, at high levels, hoard white crafting items, so that you have them "in stock".

From 4 month leagues you can load them up with crafting bases that won't cost stash space, or sell all your currency for chromatics and load up a few tabs, maybe load some of "decent" uniques that might become *cough* legacy *couch*

Funny you all mention "chaos recipe" as something that demands space? Are amulets and rings so bulky? All I keep is two full armor /weapon sets and more you simply don't need because jewelry is real limit. Rest is easy to get, as soon as I get jewelry I cash in a set.

In generel I don't keep items for chaos recipe, only store jewels and belts.

I seem to find that I'm always lacking belts, so whenever I have 2 rings, amu and a belt, the next map I'll just save an armor, gloves, etc;..