Either MEK or its close chemical cousin Acetone should attack the Loctite. Contrary to popular opinion, neither solvent is that toxic to your health. Acetone is more volatile and more flammable than MEK, but both are flammable, so work outside and not near open flames. It is best to not expose your skin to either solvent very much, as they will dissolve fats in your skin and cause dermatitis.
I have cleaned many guns and parts using MEK prior to hot bluing instead of boiling in a silicated detergent solution, and it works very well for that purpose, as MEK and Acetone are peerless degreasers. I think that using heat is the best approach to removing Loctite-ed screws.
Spray carb cleaner is very good for de-gunking guns, and it's the only thing I use. I suppose spray brake cleaner would also work, but I have not used it. They are probably close to being the same thing.