I've been having some luck with this so I thought I'd share. I've used this to polish a countertop after using a sealer-densifier product, it brings up a very good high-gloss shine and fills small imperfections. Also I've used it to repair chemical 'etched' areas like wine acidic drink stains. Parts are by volume;
1 part bees wax
3 parts high grade carnauba wax
12 parts white spirit
You have to heat this for the wax to dissolve into the spirit so be VERY careful doing this. Don't use a flame at all, use boiling hot water as your heat source and do it outside. Hot white spirit is VERY flammable, needless to say. When cool you should have a yellow wax which is JUST soft enough to apply with a cloth. If it's too hard you need to heat it up again and add more white spirit - if it's granulated or sludgy you need to heat it up again and add more wax in the same proportions 1 bees to 3 carnauba.
Hot application - this gets very good penetration so should be done for a first application. It will also seep into and 'cure' acid-etched stains where the surface has greyed as it will fill the tiny voids in the concrete with wax. Heat the surface with an electric heat gun until almost too hot to touch then apply the wax with a clean rag. Continue heating the applied wax until the white spirit evaporates off leaving the white hazy wax, then keep heating until the wax melts and seeps in (the white haze will disappear). This should happen pretty quickly. When cooled, polish with a clean microfiber cloth and remove any thicker wax build up with grade 0000 wire wool. Then follow the procedure for polishing below to give a shine.
Filling tiny surface imperfections - apply wax to the surface with a clean rag in small circles but don't allow the wax to dry. Then polish with a thoroughly wet (but not dripping) microfiber cloth. Allow to dry then polish with a dry microfiber cloth and remove any thicker wax build up with grade 0000 wire wool. Then follow the procedure for polishing below to give a shine.
Polishing - apply wax to the surface with a clean rag then immediately polish with a dry microfiber cloth. This will give a deep high-gloss shine but won't actually apply much wax. Good for maintaining finish.
Hope this is of use to someone! I keep a tin of this under the sink and can get rid of most stains or marks with it very quickly. My countertop is deep black by the way, no idea if it'll be as effective on other colours or finishes.