How would I resize the limbs of an R15 Character?

I want to resize my chars limbs and my script doesn't seem to work. Does anyone know of a method to resize limbs through script?

 game.ReplicatedStorage.Remotes.RubberEffect.OnServerEvent:connect(function()
    print("B")
    local leftHand = game.Players.LocalPlayer.Character.LeftHand
    local rightHand = game.Players.LocalPlayer.Character.RightHand
    local leftPosition = leftHand.Position
    local rightPosition = rightHand.Position
    local leftSize = leftHand.Size
    local rightSize = rightHand.Size
    if leftHand and rightHand then
        print("C")
        for i = 1, 10 do wait(0.2)
            leftSize = leftSize + Vector3.new(5, 5, 5)
            rightSize = rightSize + Vector3.new(5, 5, 5)
        end
    end
end)