pickguard adhesive remover enquiry

I've just lost a lengthy post which I can't face typing out again yet, but I have this simple enquiry too:

I've just removed the pickguard from my Sigma 000M15. The tanline is either practically invisible thankfully or I think will be after the Summer if not sooner. I haven't quite got all the adhesive off yet and have read that 'naptha' is the thing to use. It sometimes gets called lighter fluid but especially as a non-smoke I don't know if that means any lighter fluid or whether I'll have to track down naptha (can't see it on eBay as such).

Can anyone point me in the right direction or maybe otherwise suggest what to use, something safe on the finish. It's a mahogany guitar with a satin finish.

If things don't work out I'll get another pickguard but hopefully I won't have to as the guitar looks better and possibly sounds a bit brighter, plus cutting the rosette edge of the guard is a bit hit and miss and a pain. (If a luthier is reading and cuts them (tortoise shell effect only, not black) from scratch according to soundhole/rosette diameter a price is welcome.)

Thanks.