? about preservatives
 

I was told to treat my blades with selenium dioxid 70% and NA- thioanthimowat 30%. not sure if the last is spelled right. Would any agree on the use of the agents on there blades

Was the person telling you this your friend, or your enemy?
Did they describe the effect the chemicals would have, or the reason they were selected? :confused:
Selenium dioxide is an oxidizing acid, that should have the effect of turning the steel black. The other chemical may be something like ammonium thiosulfate, a photographic fixing chemical.
I think you'd be better off with mineral oil or microcrystalline wax for preserving.

Definitely stick with mineral oil or Renaisance Wax (microcrystalline wax).
The other mentioned will turn your blades various colors.

Rich