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Tips and ideas for conserving, collecting, preserving, and displaying lepidoptera.

A simple way to remove grease stains from butterfly wings.

If this has never happened to any of your specimens, consider yourself lucky. However, chances are good that you have, or will have, specimens that become stained with their own natural body greases. Some discolor immediately after being caught while others may not self-stain until months or even years later. The trigger is not always clear - it may be temperature, humidity, chemical exposure, age, etc.

Some species are more prone than others. Many Morpho species have their abdomens removed when captured to help prevent staining. It does seem to help but some specimens still stain anyway.

Two examples are shown below - a California Dogface and a Morpho Adonis. I had about a dozen old and new Dogface specimens self-stain over a year's time. The Morpho became stained during the relaxing process, either due to grease or accumulated moisture (or both). The Dogface's color is largely a result of scale pigmentation, while the Morpho gets its color from light refraction due to scale structure.

Either way the color is produced, the result is usually the same - a dark stain creeps outward across some or all of the wing area from the insect's body, and the specimen is apparently ruined.

I recently learned that the grease can be removed by soaking the specimen in acetone for a day or two. I had a number of stained specimens around that looked hopeless, so I figured I had nothing to lose by using them to test and document the procedure.

Here are the specimens with their grease stains before the tests.

Materials needed:

1 glass jar of sufficient size to contain the largest specimen(s) that you intend to process. Make sure that it has a tight-fitting lid that does not dissolve - note that some plastics dissolve in acetone!

1 quart can of acetone (if you don't already have some) about $5 from home depot (paint dept).


Place just enough acetone in the jar to allow the specimen to completely submerge. If the specimen is pinned as mine were, you will need to allow for the pin depth as well. Make sure that you remove the data label since acetone will remove many inks. Then simply drop the specimen into the drink. I let mine soak for 2 or 3 days. It may take more or less time but this worked for me.

Then carefully remove the specimen from the acetone. Note that the bug will be satuated with liquid, which is comparatively heavy, so be careful. Further, the acetone had the effect of loosening the specimen on the pin, so I took advantage of this and slid the bug up higher on the pin to better match the pinned height of the rest of my collection.

The result:

Acetone evaporates quickly, and soon I had my results. The stain was completely gone! There appeared to be no adverse effects on the specimen. Even the rose sheen on the forewing (a structural, light refraction feature) that Dogface are famous for, was still intact. Note the weird view angle of the right photo that amplifies the sheen.

Even the Morpho saw some definite improvement. It should be noted that the Morpho had some wing adhesion and wetness damage (scales missing and a wrinkled appearance) from the relaxing process, which obviously could not be removed by this process.

Side-by-side comparison:

Here's another batch of Dogface I ran the through the wash, with the same great results...

...and there you have it. Please let me know your successes and failures using this technique!

Note: Be sure and strain the acetone through a fine piece of cloth in between uses to prevent residual scales from being deposited on subsequent specimens. I found a few reflective blue Morpho scales scattered on the wings of the next specimens I dunked. Interesting effect, but probably not a good idea unless you are trying to create something new! Most of the stray scales just blew-off, but some stubborn ones remained, and I could not remove them.

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