Let me be clear at the beginning. I have not tried this and am presenting it for discussion only.
I have worked with needles and syringes for years but have not used oil based drugs. My Idea would be, to put half a cc of saline in the syringe before you pulled up an oil-based drug. with the syringe facing needle down,the saline would separate to the plunger (unless the oil is very light, in which case you would need to tilt the syringe the other way) . If you kept the syringe tilted somewhat in this plane, you would flush all the drug from the syringe first. When the saline finally passed through the needle there should be no drug left in the hub.
I know there isn't allot of volume in the hub but if you are going to pay for it you might as well use it all.
Joeyc:dg: