So you want to extract with Alcohol and do a *defat* before with Naphtha - which means using Naphtha before doing the REAL extraction to try to get other unwanted stuff out of your Seeds?
Well I'm not sure if LSA dissolves in Naphtha, but I would rather say no ... but better wait until somebody with personal experience may give his thoughts on this.
So basically when it's not soluble you could definetly do a Naphtha soak before doing the alcohol extraction.
But to the other point:
If your Naphtha has a residue, then I dont see any easy way of using it and still be 100% safe that you dont get that residue in your product.
If soak seeds with vegetable oil after doing a Naphtha pull, the vegetable oil may catch up the residue, but afterwards you will not be able to 100 % clean off the oil. It does not evaporate fully after decanting, so the residue maaay be still present in tiny amounts. Also therefore just letting it dry will also not remove anything - if the Naphtha residue also not evaporates after some time - but I guess you tested it and it still leaves a residue after 24 h ? If not, leaving the seeds to dry for 24 h may get rid of that residue nevertheless.
What you could do:
Even though that residue will not be soluble in water you could excessively wash the seeds after doing a Naphtha pull to mechanically remove that residue.
Otherwise just throwing them into alcohol and swirl them around for some seconds may dissolve the residue, but not alraedy extract your LSA. So you may throw it into alcohol for some seconds and then separate the seeds from it, that way you may remove any residue nearly completely I guess
