Liquid smoke

Don't make your own.  You could wreck your engine.  Leave it to the experts.

I have the nada smoke, but it takes a while to have the old scents burn out of your engine so I am not sure you will get immediate results either.  It may also be that smoke is smoke and will irritate your wife no matter whether it has a particular scent.

Have you tried Vanilla Mega Smoke?  Smells good.

.....

Dennis 

try going smokeless

I love Nada, and have had great results in engines which have never had any other smoke fluid in it. The rest, still have some residual scents in it. Megasteam is starting to make a product called Eliminator which is to remove the old scents. So far, it seems to be working for me, but I have only tried it once so far.

Everyone's physiology is different. While the folk lore is that Jeff designed Megasteam to allieve his allergies, it still plays **** with mine. Sometimes it's the scent, sometimes it's just the vapor itself.

You can try nada and see how your wife likes it.

As Michael mentioned, you may want to try Eliminator first to kill off the residual scent of the old fluid.