Is there a way to mute all slash noteheads?
Noteheads or voices?
Voices? Yes.
Filter all slash voices and then suppress playback via the Properties panel.
Noteheads? Iām not sure.
I mean noteheads. I still try to avoid using voices because it slows me down.
Set midi velocities to zero or as close to zero as possible?
I think @RoelVanWijkās asking for a way to mute them in bulk.
Yes please, Iād like to have oversized slash noteheads to make no sound. Ever. Also the ones Iām going to make in the future. If possible at all projects, so a one time setting. That would be great, and also rather logical, I think Iām not the only one who would want that.
Youāre definitely not.
Enter them as Slash Voices and they donāt. Ever. If you enter a note and change the notehead set to make them slashes, then yes, you will have to mute (suppress playback) them. If you simply input them as a slash voice then they are already muted and you donāt have to bother with any of that.
Yeah Todd, but remember, he doesnāt want to use voicesā¦
According to the manual, while in note entry, āTo create a new slash voice, press Shift-Alt/Opt-V.ā I donāt really see how that would slow one down. @FredGUnn has the correct approach if you want to work quickly! 
ā Jim
Ok, Iāll try that again. But it seems to cause strange things like rests ehere I donāt want them. They are deletable, but then I get into trouble when changing it later and thereās no rest anymore. I think my brain doesnāt work the way Dorico wants. Just like not being able to select bars and delete them. And donāt say that I have to use the āmaster barā because that causes even more trouble. I think Iāll have to suffer, but will try to give āvoicesā another go!