Citrus gel is good for chewing gum, blue tac, tar, oil, some paints. Its main purpose was as a spotter to use on bitumen backed tiles as it sits on the surface and doesn't melt the bitumen as a liquid solvent would.
You really need a range of solvents in your spotting kit especially when dealing with tape adhesives. There are some where I have just given up and was unable to remove it 100%.