To remove stuck invisible jigs without having to guess how or where to click on them, if these are ever part of a problem...
The MasterController way: On the ground of the lot or its lot map tag, NRaas > MC > Object Stats > Non-Inventory and click on anything that has "jig" in the name to Flush (force delete). (MC Cheats module required)
The other way: Retreat to Edit Town, evict the entire household to the side of the screen, copy the uninhabited house down to the bin, bulldoze, replace with a copy, move everyone back in without having left the screen. More intrusive than the MC way, but jigs cannot survive this kind of reset.
Where this gets really tricky is when the jigs are on the world lot (not on any other residential or community lot officially) or seem to be in between. We can't bulldoze and reset the world lot, but with some fussing around MC can usually reach them eventually.