The naptha is a bit light yellowish? is there such thing as an expiration?

all i know is that once it has been basified it starts to degrade, no idea how slow it degrades, thats me two cents.

It should still be alright, though your pull may be a little more oily than normal (the yellow stuff). It takes longer than you would think for DMT to degrade, especially when it's not exposed to oxygen.

DMT freebase is fairly stable. You can definitely put DMT from the basic soup after a month. The solvent may also have picked up some oils/fats so you might wanna consider doing a sodium carbonate wash on it. I reuse my naphtha and a few sodium carbonate washes will remove all the yellow from it after an extraction.

yes, you can but I would do also re-x after that because its likely to be not the purest product