If you expose your cyanotypes long enough, until only the specular high lights
remain green on the print,. your final print will be a beautiful blue.
As Judy says peroxide will make no long term difference. Dichromate does though.
The effect of HCl is similar to that of ferri in silver printing; it bleaches
the high lights but removes subtlety of gradation.
As to the archive, is it classified a la Dewey ? I have not used it yet.
Terry King