# Chapter 9 Restoring and cleaning damaged stamps

This chapter was last modified on 21 November, 1997.

Please send all bug reports, additions etc. to the Editor, Kaleb S. KEITHLEY. Make certain RCSFAQ appears in the subject.

## Section 9.1 Removing Sellotape

There has been a discussion about removing Scotch tape from stamps, and several people advised using acetone. Somebody wrote:

    >    I  have been  following this  thread re.   scotch tape  for the  last
    > couple of  days..  Be  very careful!!!   Acetone is  a highly  toxic and
    > volatile chemical solvent.

Jerry Morine writes: I have been following the discussion of acetone and think it may be a bit of an exaggeration to say it is `highly toxic.' The question that follows is `compared to what?'.

The most recent Threshold Limit Values (TLV's) that I have for some common chemicals are (in units of mg per cubic meter):

         Acetone 1780
         Acetic acid (vinegar is a 5% solution in water) 25
         Ethyl alcohol (grain alcohol) 1880
         Methyl alcohol (wood alcohol) 262
         Methyl ethyl ketone 590
         Sulfur dioxide 5
         Xylenes 430
         Ethyl ether 1210
         Formaldehyde 1.2

The TLV is defined as the highest concentration in air that a worker in average health can experience for 8 hours a day, day after day, without experiencing any long-term health effects. Thus, acetone vapors have essentially the same toxicity as ethyl alcohol vapors. If this is an unacceptable risk to you, you should avoid it, but make sure your alternative isn't even more toxic. TLV's are issued by the ACGIH and are usually close to or the same as OSHA's Permissable Exposure Limits.

One would want to use any volatile solvent in a well-ventilated area and store the remained safely or dispose of the remainder. A high school chemistry teacher would probably be glad to take it off your hands. Acetone is more volatile than lighter fluid, and therefore is a somewhat larger fire hazard.

Acetone can also be purchased in hobby shops and some drugstores. Some fingernail polish remover is acetone, some is ethyl acetate. Either might work for removing tape adhesive.

Martti Tolvanen writes: Acetone is volatile and highly flammable, but as to toxicity it's one of the least toxic organic solvents. I wouldn't drink it, though ;-).

In Finland you can buy it from pharmacies, or if you have friends in a chemistry lab, you can ask them to give you a small amount.

One more comment on paint store acetone: I'd suspect it to be of so impure quality that I wouldn't soak my stamps in it. Same applies to lighter fluid.

Thaddeus P. Bejnar writes:

Finger nail polish remover often contains perfume or other oils that can damage the stamps. It is much better to get the acetone from a hardware store.

Usually it is in pints. Be sure and soak the stamp(s) in a closed container since the acetone is highly volitile (evaporates very quickly). Don't breath the fumes, or over time you risk liver damage.

Similarly, the suggestion about brake fluid as a solvent, must be evaluated against the residue (oils) that may be left on the stamp(s). Has anyone tried brake fluid?

I did notice color changes in a number of stamps with the use of acetone.

Nicholas G. Carter writes: Although I have never tried (brake fluid), I have used it to remove paint from plastic railroad models (in fact this is the hobby's recommended method). I suspect it would remove inks on stamps rather readily.

Bjørn P. Munch writes:

    > Ask  your girlfriend  or  wife  to borrow  their  finger nail  polish
    > remover.  Most are nearly pure acetone.

(So it can't be *that* toxic)

Don't these usually include some oils, to prevent the nails from drying out? If so, you may risk getting an `oily' stamp.

I haven't tried this - I use pure acetone bought at the drugstore.

# Chapter 9