How to delete selection boxes?

So I'm making this plugin where it turns all the bricks into outlines with the use of selection boxes. My problem is that when I go to reverse the function, it doesn't delete all the selection boxes, only a few of them. Please help!

for _, v in ipairs(game.Workspace:GetChildren()) do
    if (v.ClassName == "Part") or (v.ClassName == "WedgePart") then
        v.Transparency = 1  
        local Part = v
        local box = Instance.new("SelectionBox", v)
        box.Adornee = Part
        box.Color = BrickColor.new("Really black")
    end
end

for _, v in ipairs(game.Workspace:GetChildren()) do
    if (((v.ClassName == "Part") or (v.ClassName == "WedgePart")) and (v.Transparency == 1)) then
        v.SelectionBox:remove()         
        v.Transparency = 0
    end
end