In our workshop we have been trialing using Clarinet Bore oil (La Tromba) to also condition fret boards. if you leave it to soak over night, it penetrates the wood more consistently and evaporates far less quickly than lemon oil. This has now become standard practice for the guitar techs in our workspace.
Honestly I just take it in to get cleaned by a professional, my thought process is - why risk damaging my guitar, when there are experts who can do it better? If you can afford it, definitely rely on a professional.