Q. Some of us instead of washing jeans and sweaters that fade and look worn out after only a few washes, place the pieces in the freezer for a day and it works just fine. See: hhtps. housekeeping. wonderhowto.com. Are you allowed to freeze your clothing during the nine days?
A. From the above link I quote: “According to Jill Guenza of Levi Strauss, jeans develop bacteria over time and wear that causes them to smell. When they start to get stinky, we tend to toss them into the wash—but that's what wears both their fabric and color down. Guenza instead recommends sticking your jeans in the freezer, where the bacteria can be killed by the cold temperatures and rid the fabric of its odors.”
Horav Shlomo Miller’s Shlit’a opinion is that if the freezing is the only “cleaning factor” involved, it may be permitted during the Nine Days. The Rov asked to verify if condensation may be also part of the process. I did not find any mention of it on line. I did find was a suggestion to defrost by using the microwave oven, which is a more effective way to kill bacteria. That would also be permitted during the Nine Days.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a