ok everybody seems to be having fun with you..lol..
but as far as i know the one ingredient to be wary of is toluene, google it. oil resistant white glue (orwg) is supposedly the safe bet.
as far as your concern of seeping into your brain, well i doubt that is a concern. what one would be concerned with is chemicals being absorbed into your body.
now i have no evidence, but it would appear to make sense......that if you arent putting processed foods, grains (even the supposedly healthy ones) gmo's etc into your body and have a good, clean and at least some what organic diet your body is probably not over loaded with toxins and should be running as designed. what i mean is that your body would probably be able to eliminate what it comes in contact with.
go to youtube and search the The Story of Cosmetics (2010) for some great info..get the movie called genetic roulette- the gamble of our lives and what i'm talking about will make more sense.