This has been asked before in another thread (im not sure if it was on this forum though.

But I have done naptha pulls on a STB, and the little bit of naptha that I couldn't get mixed with the next pull I did with xylene.

Is it possible to do naptha FASAs? I remember someone saying it caused a reaction that screwed everything up and im guessing the other guy who opened a thread thought the same thing because he had the same dilemma.

Will my naptha contaminated xylene affect my FASA Fumarates crashing out? Is it going to be bad? Should I just evap that xylene pull?

It should work fine - DMT fumarate is a salt and so is generally insoluble in non-polar solvents.

You will have a combination of three solvents if you try this. Naphtha and FASA is reported to not work. Xylene FASA is reported to be good. Without testing it would be hard to know how the combination would behave.

Either mix up the same solvent ratio and test to see if FASA drops acid from a clean mix with no dmt. Or do FASW or vinegar salting which will both work fine as the acid is dissolved in the polar layer and will not enter your solvent mix.

I would go for the second option myself and use fasw

Hope this helps a bit.