I use Berp bio-oils on all my brass instruments. It works and it’s smells so much better than mineral oils.

Berp works as well as any oil, but BERP smells nice and is much more ecologically friendly.

These products work well with my Gebr Alexander instruments, they appear to last longer than other products which is very useful for my descant horn which I use least and they have a pleasant citrus odour. In Eco terms they're plant based which would seem to be more sustainable and less toxic.
Paxman were very prompt in sending these products out with their usual helpfulness which is much appreciated.

Have used a mineral based oil before. This seems to be as good and cleaned the valves well and has produced a silky smooth response. Whether it will continue to do so; the juries out.