TYPE
"r_drawviewmodel 0" hides your weapon
"cl_drawhud 0" to hide your hud
"hud_saytext_time 0" to hide chat messages even if people continue to type out new messages
"hud_deathnotic_time 0" to make icons that tell who killed who with what hide
I usually bind mines like so:
Bind mouse30 "r_drawviewmodel 0; hud_saytext_time 0; hud_deathnotice_time 0; cl_drawhud 0"
Bind mouse31 "r_drawviewmodel 1; hud_saytext_time 11; hud_deathnotice_time 6; cl_drawhud 1"
hope it helps