Here's an article you might find interesting. It tells you about how waterfall came into popularity, how it was made, what not to use to clean it. Some interesting stories about it. (Such as why so many pieces made and that we still see today are bedroom suites. Depression era couples often started out living with parents, so had nothing much to call their own except their bedroom furniture - if they could afford that.) Click on What is Waterfall, Anyway? I'd be very leery of Krud Kutter on wood, but especially delicate, aged veneers. That's a degreaser meant for everything from aluminum siding to garage floors. There are lots of recipes out there for cleaning antique wood. I have a routine I like. Start with Formby's Deep Cleansing Build-Up Remover. Just be careful with any loose veneer, some of it could be about paper thin and not take a lot of pressure. I like Restore-A-Finish for pieces that need spruced up but not a full strip and restore. It's worked wonders on solid wood. If using on veneers, avoid the steel wool it says you can use. Too harsh on veneer imho. When you've got it nice and clean, consider a good paste wax like Trewax or I like the liquid Howard's Beeswax Feed N Wax (Sears Hardware, Ace). If someone in a store suggests Bowling Alley wax, I'd suggest avoiding it. It was recommended to me by a retailer who said a couple of his 'old-timer' antique dealing customers use it. That stuff was about impossible to buff out and was kind of gummy feeling to me. My SIL gave me a beautiful deco era waterfall accent table, from DHs grandparents. She just didn't want it anymore. I just did a light RAF wipe rather than a lot of elbow grease with super fine steel wool. Didn't want to risk harming the veneers. Anyway, I did my Formby's, RAF, Howard's Beeswax routine and sent her a photo with a thank you. She was amazed at the difference and wanted to know what I refinished it with. ;) This is a different piece, before and after. An ebay purchase, a vintage solid cherry hutch in pristine condition structurally but had smoke film on it and other kinds of grime, the finish was dull and needed a really good cleaning. seller's photo after I did my Formby's>RAF>Feed n Wax routine.

The terminology gets a bit sloppy and is certainly not helped by centuries of finish chemistry and manufacturer's labels. When most people think of "varnish" they are referring to a product produced by heating an oil with a resin to create a new substance. This substance is then thinned to create a brushing or wiping consistency. So: heat Resin + Oil ------> Varnish Varnish + some thinner ---> brushing varnish Varnish + more thinner ---> wiping varnish 1 part varnish + 2 parts (additional) oil + 6 parts thinner --> Danish oil (more or less, depending upon mfr formula) teak oil, antique oil, etc. The common oils are : Linseed, soy, and tung. The common resins are: urethane, alkyd, and phenolic, or some combination. Arcane formulas for violin varnish, etc., would use natural resins, but we're unlikely to see those in a can anywhere. The thinner is usually a petroleum distillate such as mineral spirits. Some people call anything that dries by evaporation a "lacquer." So that would include shellac (sometimes labelled padding lacquers) and some even stretch it to include acrylic finishes (the so-called water borne lacquers, that cure only partially by evaporation). But when most people think lacquer, they think of nitrocellulose lacquers, or perhaps CAB lacquers. It's a shame there is such confusion. It's one of the things that makes finishing more complex (and hated) than it really needs to be.

Shellac is the best odor barrier you can use. You can use clear such as Seal Coat or pigmented such as BIN Primer. Both are by Zinsser who is the singular major importer of shellac in the US. You might also wash down the boards with a rag dampened in denatured alcohol prior to applying the shellac. The article below explains a good method for cleaning. Here is a link that might be useful: Saving the finish

Mostly, it looks "splotchy" because of the type of wood it is. You would need to sand it down completely, using an orbital sander. Do a test to see what grit to start with (maybe "100"). This will depend on what type of sealer is over the stain. Then do progressive grits - 100, 120, 150 & 180. Don't skip any. Finish by hand with the 180, going in the direction of the grain. Hopefully you can do color tests on the back of the leaves or table. You will need to seal the wood before you stain it to prevent as much blotching as possible. Or you can look into "toning" it with water based stains. Are you able to spray on your finish? Do some internet research for the "best way to refinish a table" (insert the wood type).