
1. Wax Polish
This is a semisolid polish and does almost no harm to the wooden surface and is widely used in India. It involves a lot of physical labour. Since it is stable and durable, it needs to be applied infrequently. Polish gives a natural and penetrating appearance rather than film-building look to the furniture. It usually has a dull sheen look to it.

Varnish is a combination of drying oil, resin and a thinner. It usually gives a glossy look though it may be designed to produce satin or semi-gloss look. Usually varnished surface is sanded carefully and then varnish remover is used which can be found in hardware stores. Be careful because there are some varnishes that stay permanent.

It is easy to indentify paint on wood due to its different colour. Most paints are oil based and can be removed with thinners or paint removers.

Shellac is derived from a resin that is secreted from an insect native to certain forests in Southeast Asia. Shellac is non-toxic and can be added to any colour very easily. To determine shellac finish, use mineral spirit or turpentine and rub it with a white soft cotton rag in an inconspicuous area. The apply denatured alcohol to the spot and leave it for 5 minutes. If the colour dissolves and the rag picks up the colour of the furniture, then it is a shellac finish.
Lacquer is a coloured or clear varnish which produces is very hard and durable look. It comes off effectively only with the lacquer solvent.
Simple home cleaner and more....
Use warm water and detergent to clean finishes and leave it to dry for a while. Mostly it does works on painted and clear finishes. Do not pour the solution on the wood as it may open up the wood grain and cause damage to it. Soak the cotton rag in water, rinse it dry and then work in sections by wiping it. Take another clean rag and dry the surface again.
2. Thinners
There are several types of thinners. You can find paint, polish, metal...etc thinners at any hardware store. They are easy to use and are very widely used in cleaning surfaces in India.
Mineral spirits and turpentine are two different solvents which have similar applications. They both are very good in case there are grease or oil stains and work great on painted and primered surfaces. This one is widely used in restoring furniture. In India turpentine is widely used though working with mineral spirits is easier and safer. These are usually available at paint shops.
Denatured alcohol is weaker and slow-working and good to clean light surfaces. It helps to more easily remove the excess dust that results from sanding wood, because it does not open the wood grain. It is widely used for shellac finishes.
Lacquer solvents are strong and will dissolve them quickly. They are used on lacquer finishes only.
Hope you have got an idea about the different types of finishes that appear on the piece of furniture you want to restore. I will certainly talk more about removing spots, grease and water marks in my next article. For now please try to understand and care for your furniture. Always remember, old is gold. Restore and treasure it as much as you can!!
My first computer was a Sinclair ZX-80, but it had no connectivity. I mostly just built loops and other useless apps in Basic. Network connectivity for me came in 1983 with an Atari 800 and a 300 baud modem. Would log into the National Weather Service, NOAA etc. Then joined TheSource, and upgraded to a 1200 baud Hayes smartmodem and an Atari 1200XL. Also had an Apple IIc and a TRS-80. Played Defender until my palms would literally bleed. Never failed to set the high score in numerous arcades around the country.
By 1984 I was using a Fortune Systems 32:16 (still have it!). Played games, logged into various government sites, and 'chatted' with others when I wasn't building rudimentary accounting software (a checkbook balancer and order-entry system) and unix shells for small office environments. Joined Compuserve, read news from The Columbus Dispatch (lived an hour down the road) and various other sources.
During this time I earned my Computer Science degree initially using a Honeywell system (punch cards!); later, a PDP-11. Had 'email' starting in 1983. Suffered through Fortran, LISP, some Cobol, and Assembler. Have done no programming since 1986, though I did teach myself html and built several websites in the mid-1990's.