CS>Brooks Bradley Mix

[Melly Bag]

Hi All,
 
I am a user of the Brooks Bradley Mix and love it.  
 
I have a question, i am thinking of adding a bit of urea and allantoin, does 
anyone know if this would be safe taking into account that DMSO brings 
everything even up to the brain?  How much of each should i put?
 
Many thanks for any advice you can give.
 
Melly