How Does Washing Change Stamp Value?

I see a lot of early stamps offered that appear to have been washed, mainly, I assume, to lighten the cork cancel.

Any guidelines or thoughts about how washing effects value?

TIA

Burnside

It's considered a major fault, especially when it effects the overall color and quality of the stamp. It should be considered the same as a 4mm tear in the stamp...
"Washing" is ok as long as it's water. Chemically altering is another matter altogether. Any attempt to "lighten" a cancel is a major alteration. As as rule of thumb, I would say it makes the value of the stamp 10% - 25% of the CV.
I have "washed" a few stamps in my day to remove stains or improve the quality of the stamp, but this is done only in water, and on rare occasions a little soap, particularly when the stamp is already so bad that you can't make it worse. This is quite different from chemical alteration.
Nothing wrong with removing stains or objects stuck to a stamp (particularly used ones) where you're not altering or damaging it.

Agreed. Washing in water to remove dirt, hinges etc. is a good thing. You'll sometimes run the risk of exposing thins etc. but it's better to know these things, particularly if it's not a super common stamp.

In my opinion using soap is also an alteration. Laundry and dishing washing soaps have optical brightens added to make clothes and dishes look better. The same optical brighteners make stamps look better but using them can cause your stamps to light up like a Christmas tree under a UV lamp.

I worked second shift in a textile mill during my college years. We added optical brighteners to all white textiles to induce people to buy them. The optical brighteners are basically small reflective particles, they make the item look brighter to your eye. They also react under UV light.

I do not know if certifying organizations check to see if a stamp has had optical brighteners added but I recommend soaking stamps in clear, cool water only.
Don

I've never used soap or salt or anything like that when soaking stamps, but I will use water just off the boil if I know the ink isn't fugitive. It's especially effective at quickly getting hinge remains off without getting the stamp too waterlogged.

I've found cold water is best. No chance of any damage or alteration from heat.

Soak until hinges drop, remove to a page towel, then place in a drying book or press. I use a press.

Let them remain in the drying book/press for a day and then put them in your collection.

Thanks for the informative replies. I was unaware micro beads might be used to brighten stamps--had heard about micro beads used in whitening tooth pastes!!

Secondary to my first question--will expertizers note that a stamp has been washed?

And is there an online resource that illustrates appropriate color for each stamp that can be used as a reference?

TIA again.

Burnside

Burnside Bob: I've never seen a cert noting cleaning (as we are talking about here, with water only, or with light soap), but they DO take note of cancels being removed (or ATTEMPTED to be removed) and of stamps being faded or color altered. I use warm water on color-fast stamps and I let them soak a while - after they come off the paper (or the hinge on the back comes off) the glue can still be there, so I let them soak longer to let the glue dissolve completely. There are plenty of stamps that I don't soak because the water will fade/damage the ink used in the printing. Based on what Don said upthread though, I will hold back on the soap. Generally, I was using like one drop of dish soap per quart of water. I would NOT use anything other than what has been mentioned here. About the only other fluid I would stick a stamp into would be some type of watermark fluid to look for hidden things. And also don't 'rub' a wet stamp too much (I am tempted to rub a wet stamp to 'rub off' a stubborn stain) because the paper is so vulnerable to mechanical damage when wet.

Couple points of clarity to this:
1. I'm not recommending using a soap on every stamp... only stamps that are so far deteriorated by some other "defect" that you can't make it worse by cleaning it. Here is an example of when a stamp is ok to have some cleaning done.




There is no chance to make this worse.
Not all soaps contain optical brighteners. Laundry soaps are the most common, and most do have, but I wouldn't recommend using them anyway. Dish soaps do not (in fact, I can't find a single dish soap that contains an optical brightener). Not saying they don't exist, but I am saying, majority of dish soaps are safe (not including dishwasher soaps).

So that wasn't enough for me, I want to debunk this myth that using a light soap emulation to remove unwanted dirt from a stamp neither a) alters the paper or fibers, nor b) alters the color, either short term OR long term.

Today I ran a test. Here is what I did.
I randomly selected 6 219's from my vat of about 400 of them to use in this test:
1. Control - These stamps had nothing done to them.
2. Water only - These stamps were submerged in cold water only for 3 minutes
3. Soap emulation (just used my counter top dish washing liquid) Soaked them in the liquid for 2 minutes, then rubbed them gently between thumb and index finger for 1 minute, dipped back into the same emulation only to get the soap off of them.

Then, I took them out. There are 2 of each stamp "exposed" to the 3 conditions above.
I took photos of them in natural light which are presented here:



This is the regular light image.
These two images are under a UV-B (very strong) black light. I also tried it with a UV-A 380nm light (very light), a UV-A 254nm light (pretty strong) black light as well. But the STRONGEST result comes from my 10BL-B UV-B light, so I went with that.

This image is the top row under UV:


And this is bottom row under UV:



So my challenge is this:
I will allow the pick of your choice from my dealer stock, nothing off limits, to anyone who can accurately identify which 2 were washed in soap, which 2 were soaked in water, and which 2 were the control (just pulled out of the binder).

My point here is this: A light washing of a stamp is most certainly NOT an alteration of the paper OR the color. There is nothing wrong with stamp preservation. There are advocates for some stamps (particularly CSA) even to soak of their OG because IT is damaging the stamp! (I see both points of this argument actually).
But to argue that removal of dust, dirt, grease, or other soil is an "alteration of the stamp" is just misinformed.
AND this "Myth" and "fear mongering" of attempting to do so, irreversibly alters the stamp to some degree that is detectable by any reasonable means. (Sure, if you expose it to chromatic spectrograph, you may be able to detect the presence of some substance, but I submit that if you subject a stamp to 10,000x magnification you will ALWAYS find a fault in it as well).

Finally attached is an example of CHEMICAL CLEANING, which clearly alters the stamp both in visible and UV light. The stamp on the left was chemically cleaned. Guess what, compare it to any other stamp, and you will be able to EASILY identify it as such, and if not, stick it under a UV light and it will be obvious.

Visible Light:



Back under UV Light:



The stamp on the left (A 73) has been chemically cleaned. The design still looks "fresh", the paper is almost "bleach-like". It has a different feel to unaltered 73's, but the design has minimal loss of coloration (this is particularly effective in black stamps, some stamps like the Grey Blue/Ultramarine 206 will turn "monochrome" in some solutions.)

So the gauntlet is dropped. Let's stop the myth that washing a soiled stamp is a bad idea. Done right, it's really not.

Note on edit: Corrected a auto-correct typo from "solicitations" to "solutions".

Your thoughts: My grandmother, who introduced me to stamp collecting, used to sware by putting a dash of hydrogen peroxide in her soaking water. It's been years since I soaked any stamps, but I seem to recall that the extra oxygen would freshen the stamp's color by de-oxidizing. This was especially apparent on the oranges and reds (was told that this was due to the use of iron in the pigment that would oxidize (rust) over time, so the hydrogen peroxide would bring it back toward its original color. I'm assuming that her recipe would be frowned upon as a chemical alteration. But, since hydrogen peroxide is just water with a bit of extra Oxygen floating around (H2O2), perhaps not. Thoughts?