This is sooooooo effective. Before usage, I took a drop of terpentine and teatree oil to get rid of rosin residues, then applied this for all the cello body and voila! It took just about 10 mins with this restore the surfaces to their previous glory. My God, it is so large bottle so I think the product will last for decades! When using for the first time, don't get overconfident, choose not so wide area to treat with the product, the point is that you have few minutes to clean and then polish (so be preapred with at least TWO clean wipes) for the best results. Every time you use it you shake the bottle and you are good to go.
Of course, sometimes you may need to visit your luthier for re-varnishing, but in every other case it gets the job done.
Some websites say: "To be used by professional luthiers only". When you read and follow the manual, you become a professional detailer yourself.
Greatly recommended.