Disabling Sprays on a Server and why can I never see sprays?

Simple question really. How do I disable sprays on my server? Every convar people tell me to put never disables them. Also I can’t see sprays. I never have been able to. Does anyone know why that might be?

Add a file into lua/autorun/server by the name of “disablespray.lua” and add this into it:

[lua]hook.Add( “PlayerSpray”, function( Player ) return false end )[/lua]

I believe doing sv_allowupload 0 will also disable sprays.