Temper Etching Question

We do Nital/Temper Etching and per AMS 2649 we're allowed to use an anti-smutting agent that will allow us to skip the hydrochloric acid de-smut step and eliminate the hydrogen embrittlement bake.  A thorough search of the internet, though, reveals nothing.  I was wondering if anyone on here knows of a good anti-smutting agent for nitric acid.