You can't edit accessories via script?

I'm able to edit other things like Heads and Torso/UpperTorso and such, but I cannot seem to edit accessories.

local Player = game:GetService'Players'.LocalPlayer
local Character = Player.Character or Player.CharacterAdded:Wait()

head = game.Players.LocalPlayer.Character.Head
crow = game.Players.LocalPlayer.Character.Shouldercrow

workspace.Part.ClickDetector.MouseClick:connect(function()
    head.Mesh.Scale = head.Mesh.Scale + Vector3.new(1,1,1)
    crow.Mesh.Scale = crow.Mesh.Scale + Vector3.new(1,0,1)
end)

20:55:16.511 - Shouldercrow is not a valid member of Model