A. Thrip-cloth Method (using a silk cloth) for lettuce (romaine, etc.):
You will need a large bowl, dish soap, 2 strainers, a thrip-cloth, and a light box.
1. Separate the leaves and place them into a bowl of water.
2. Put enough dish soap (a good choice would be Seventh Generation 0% fragrance) or kosher vegetable wash into the bowl until the water and leaves become somewhat slippery.
3. Agitate and soak the leaves in the soapy water for 1- 2 minutes.
4. Remove the leaves from the bowl, and discard the water.
5. Repeat steps 2-4. Alternatively (instead of repeating steps 2-4) one can wash each leaf under running water (both sides) and then place leaves into a new bowl of soapy water.
6. Place leaves into a bowl of fresh soapy water, and agitate for 1-2 minutes.
7. Remove leaves and pour the water through a thrip-cloth (fine silk cloth that can be purchased at https://www.crcweb.org/books.php) that is sandwiched between 2 strainers.
8. Check the cloth carefully on top of a ight box. If no insects are found, put the leaves back into plain water, soak and agitate for a minute, remove leaves, and enjoy. If an insect is found, repeat Steps 6-8. If insects are found after doing these procedures 3 times, the produce is overly infested and should be discarded.
B. Alternate Method if no thrip-cloth is available:
For large, flat leafy vegetables (does not include curly greens, such as kale):
1. Prepare a bowl of water and put in enough dish soap or kosher vegetable wash that the water feels somewhat slippery.
2. Separate the leaves from the heart and put them into the bowl.
3. Agitate the leaves for 1 minute.
4. Remove leaves from soapy water and discard the water.
5. Gently rub all areas on both sides of every leaf with a sponge. This includes flattening the curled-up edges of the leaves so they can be scrubbed.
6. Rinse each leaf under a stream of water while running your fingers across the leaf to undo the folds.
7. Place the leaves into the second bowl of soapy water and repeat Steps #2-6. In this repetition there is no need to scrub the leaves with a sponge.
C. For small leaf vegetables such as parsley, cilantro and other herbs:
Follow steps 2-5 of the thrip-cloth cleaning method. One may then check the water using a clear basin in bright light very carefully for insects. (Please note that a lot of time is needed when checking the water as the insects will be harder to see when floating in water.) If there are insects found in the water, the process should be repeated until no insects are found in the water. Then three samples or batches of the vegetable must be checked and if no bugs are found, the remaining produce may be used without further checking.
Please note that we do not recommend the use of salt water or vinegar to properly remove insects from fruits and vegetables. Another important point is that many times one comes across a fruit or vegetable that is unusually infested with insects. This is especially true with most organic produce. If left with no choice, the only way organic or highly infested produce can be consumed is if the above mentioned “thrip-cloth method” is used and repeated until the produce is clean. If after three times there are still bugs on the cloth, either throw out the batch, or continue the thrip cloth method until you have clean cloths twice in a row. Finally, when discussing bagged lettuces we are not recommending them for the Pesach season, unless purchased before Pesach, as there is an additional concern of non-Pesach ingredients used in the wash.
To see images of common insects, see here: https://consumer.crckosher.org/publications/insect-images/