Hi Hany,
Looks like a crude oil or something like naphtha and I easily recognize the main hexane isomers.
For a naphtha I would use the sample as wash solvent, but for crude(r) material I would use mixed hexane since it is not a single component solvent, even though (also because) your sample has hexane in it any carryover will be less significant this way.
Carbon disulfide is another option for wash solvent when running naphtha or crude oil samples. It's response on FID is low compared to hydrocarbons, so there should be little to no response if some residual is in the syringe.