You have two of the same variables, if the 2nd line in your script doesn’t serve any purpose then I advise you remove it as it could be causing the complications.
I also believe you’re trying to check if the box is in workspace for the 8-10th line? Instead of a numerical value you can just do:
If game.Workspace:FindFirstChild("box") then
game.Workspace.box:Destroy()
end
:FindFirstChild() checks the descendant you define, this being workspace, so you’re essentially checking if you find the box in workspace, and if you do you destroy it.
My memory is dodgy which is why I didn’t mention this earlier, but I’m not entirely sure if you can clone a part locally, I think your best bet is to make use of Remote Functions and Events in order to help you do this, but if a better solution comes up definitely use that.