Welcome to the forum.
Well material removal, is dependent on what you're trying to take off, so a more accurate idea of what it is will help. It might simply be a thick coating of furniture wax, but could also be spilled Coca Cola. It also depends on what you're trying to do, just remove the coating, so it can be refinished or wholesale surface prep, which removes varnish, stain, etc.
Usually it's best to "sneak up on it", first with mild soap and water, dry and see what you get. Next a harsher soap, then you'd move to chemicals, possibly in combinations (be careful, you can make a big, possibly toxic mess). I'd first start with white vinegar, to dissolve any organics, like furniture wax or spilled soda. Next would be mineral spirits, which will leave an oily residue, but is easily removed or left to evaporate. The nice thing about mineral spirits is it's low evaporation rate and it's friendly to most finishes, particularly varnishes and polyurethanes. If you move up into some of the more harsh chemicals, like toluene and acetone, you will affect the finish and underlying stain, plus you might have over coating issues when the time comes, unless you're just going to paint.
Lastly, don't "scrub" but wipe the surface with a well soaked soft cloth rag. Scrubbing will leave marks that you'll have to address later, if the finish is to remain "bright". On the other hand, scrub away if you're just going to paint. Let the chemicals do the work, your elbows will like you better.