How do I Delete a SelectionBox from a part that's in a Model?

Hello, so I'm currently stuck on this part of the script where the selection box does not disappear when the mouse is not hovering over the grass. The grass parts are inside a model called "Plots." I've also tried to do for loop to look through the plots model but then I can't figure out how to find the selectionbox inside a grass part.

`local plots = game.Workspace:WaitForChild("Plots")
local value = script.Parent:FindFirstChild("SelectionValue")
local player = game.Players.LocalPlayer

local mouse = player:GetMouse()

local box = Instance.new("SelectionBox")
box.Color3 = Color3.new(0, 255, 0)
box.LineThickness = 0.4

while wait(1) do
mouse.Move:connect(function()
    local target = mouse.Target
    if value and value.Value == true then
        if target.Name == "Grass" then
            box.Parent = target
            box.Adornee = target
        elseif target.Name ~= "Grass" then
            box.Adornee = nil
            box.Parent = nil
        end
    end
    end)
end`