So I've just trawled through 40 pages during my search and I think I've found 7 different answers to my question.
So I'm just gonna take the bull by the horns and straight up ask you guys.

I have some spice which I've stored in an airtight container in a dark closet at room temperature for 4 years. It hasn't turned to goo, but it a bit more yellow/reddish than I remembered.
I can't get a hold of zinc powder or heptane, so I'm wondering if it's enough to just do a re-x or two since oxide apparently isn't soluble in naptha?
Or should I do an A/B extraction?

Thanks in advance!

Re-x is all you need. Obviously if there's a lot of oxide you could lose a considerable amount of yield.

Great, thanks.
I don't mind losing yield, I just want it as clean as possible since I haven't smoalked in a couple of years.

If you are just washing with naphtha then make sure the naphtha is warm when you do it and you should see any goop remain at the bottom (usually oxides). Keep that goop as it is still 100% active. I can't imagine a huge amount of it oxidizes in 4 years sealed in an air tight container (freezer is even better).

I've just washed it with warm naphtha a couple of hours ago. I tossed the goop, tho. It's in the freezer now. There was 1.2g, so it'll be interesting to see how much of the spice remains.

I'm with Jega and Fathom on this. Warm naptha added drop by drop, swirl it around and poured into another dish. That is of course if you feel is necessary. Strictly speaking there's nothing particularly bad about the slight oxidation from a few years storage.

0.9g spice remained so I took a 25% loss. The color is slightly off-white. Much more pleasant to look at.
Thanks for the help!

Suggestion: one can freeze the naphtha recipient with the goop at the very bottom, I realise not many people do this. For this a large shot glass works great.
After the freeze action poor out the naphtha and let all dry for a day, then scrape off all the whites and collect those.

Then also scrape off the semi hard (sometimes bone hard!) former yellow goo at the bottom and collect that too, it is fully active material (on the condition there was no lye contamination or so). It is very much ingrained with spice and that makes it now hard to semi hard, sure manipulatable by hand for weighing etc. It can be used for oral pharma sessions, or rectal administrating (after dissolving a dose in 2 ml of standard vinegar). Mind that rectal ROA of spice asks for utilization of harmalas along, possibly oral in advance.
So far have not tried to make changa with it.

Happy trials.

I thought that the goo would contain the DMT oxide, that's why I didn't keep it. But I'll keep it in mind for next time.

Spice is polymorph and it can be goo too. There was a time people had goo or oil and no crystals and people went with that very okay. The urge for white crystals has become a hype and people started to think anything else is not okay or not pure. It's a fallacy.

Check out this one:
What are the current views, facts and theories on DMT-N-OXIDE?

I'm sure you could have found this link yourself, efforts given

changa It all and cut your losses!

IME doing an intial sodium carb wash when extracting has improved the storage of my spice. I had 2 older batches, one washed and one not washed because i didn't want to go through the extra step. The washed batch still looks like it did when i extracted it and the unwashed took a tan color.

I concur that, it's as if a sodcarb end treatment wash puts a protection onto the crystals and that goes for freebase harmalas as well.