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Cleaning old poly coated wood trim

Posted by jane__ny (My Page) on
Tue, Apr 28, 09 at 23:20

I know the trim is coated with polyurethane, but 20 years of grease, cigars, and probably old wax needs to be cleaned off. Trim is oak with an unknown stain (wood looks yellowed.)

I tried scrubbing a small section with Dawn and warm water. The sponge was filthy and it seemed to dull the area. Is this a safe way to clean the wood?

I'm hoping to avoid having to refinish.


Follow-Up Postings:

RE: Cleaning old poly coated wood trim

TSP---get it at hardware stores/paint stores.

The dish detergeant will not cut the wax and grease as well. The dullness is probably more dirt/etc.

RE: Cleaning old poly coated wood trim

TSP is very likely to damage the finish.

Plain old paint thinner will not harm poly and removes grease and grime very well.

Avoid abrasives of any type.
Paper towels and paint thinner usually does a great job.

Open the windows and test first behind a door.

RE: Cleaning old poly coated wood trim

Boy am I confused. I went to the hardware store today and bought TSP. I was planning to tackle the wood this weekend. Paint thinner won't take off the poly?

Thanks again,

RE: Cleaning old poly coated wood trim

I have used TSP---there is no P anymore---several times without harming the finish. It simply dulls is from incompletely removed crud. Rinsing a second time solves that problem as long as all the dirt/etc. is removed.

Thinner is good for wax/grease, but does not get dirt as well as TSP. No solvent will affect cured polyurethane. Strippers will, but thinner is fine.

If you are unsure, try both. Then use the one that does the best job.

RE: Cleaning old poly coated wood trim

Ok, I've waited long enough. I delayed at the risk of confusing things, but we've passed that point.

You probably need both. If you are a chemo-phobe, you can stop now.

There are two types of soiling, things that clean with water and things that don't. Specifically, water is a polar solvent and removes things like ordinary soiling, and with help of a surfactant or alkaline -- smoke, cooking greases, etc. Mineral spirits is a non-polar solvent and removes things like petroleum greases, waxes, oil, ink, shoe polish scuffs (wax), etc. Alcohols are selective solvents and dissolve a variety of things that is not always predictable.

Thinner and solvent terminology gets a bit sloppy. Mineral spirits is normally sold as "odorless" or simply "paint thinner" If it is not odorless, it contains some stronger solvents such as xylene and benzene. Naphtha is similar but less oily and faster evaporating. Naphtha is one step up on the fractional distillation scale for petroleum. Either will not dissolve varnish as it has cured by chemical reaction (oxidation and polymerization). However, there are some solvents that will definitely affect poly -- acetone comes to mind, and anything containing acetone, e.g., most lacquer thinners.

I also concur that the streaking probably means you have not sufficiently cleaned vs. damaged the finish. Tobacco smoke is really tough to remove. Try spraying some Formula 409 on a damp rag and see what it does.

RE: Cleaning old poly coated wood trim

"If it is not odorless, it contains some stronger solvents such as xylene and benzene."

Xylene is way more expensive than paint thinner, and benzine has been restricted for many years.

Orderless p[aint thinner has just been refined a little better.

Paint thinner (AKA 'Stoddard solvent') is a witches brew of hydrocarbons with similar fractionating temperatures.

It is actually a more dangerous solvent for exposure than many of the purer ones.

TSP is only resticted in certain places.
I just cross a county line and can but plain old Savogran TSP, less the clothes washing tip that used to be on the box.
The county I live in stopped the sale of all TSP for noon-commercial use. It is still used for a number of industrial applications, like hot tanking of engine blocks.

It is a very powerful product and can dull all sorts of finishes that would appear to be immune.

You really need to test it on any finish you do not want to damage before using it, and the hot water normally used with TSP does not help protect vulnerable finishes.

TSP and hot water is capable of dulling alkyd paint very nicely, and was used for many years for just this purpose.
The solvent deglossers are a PITA to use.

RE: Cleaning old poly coated wood trim

Wow, I am lost. I used Dawn and warm water and it looked cloudy. I used a sponge with a rough side and really scrubbed. Maybe I damaged the surface?

I bought a box of TSP (without the P). The man in the store told me they can't sell the real thing anymore. I'll give it a try, but maybe Fantastic or 409 would help. The grease and whatever else, is really thick in places. I think it might be grease with years of dust mixed in.

Thanks all,

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