Safe is totally in the hands of the user. Cyanide is used in gold plating and is quite safe assuming stupidity is not part of the equation (i.e. let's see what it tastes like.) Navel Jelly does a great job of disolving the rust, and that is what it was intended for. Before using though, I wire brush off the heavy rust deposits and use navel jelly sparingly as the next to final step ... the final step is cleaning :).