You can use a GUPPYFRIEND™ bag to capture microfibers when you wash your Ketos. 
Basically, every time you wash synthetic fabrics they shed small plastic pieces called microfibers, which is leading to plastic pollution of our waterways. We use recycled synthetics to lessen our environmental impact, but these potentially shed microfibers too. Microfibers are too small to be filtered out by waste treatment plants, so they end up in our waterways and oceans. Once in the ocean, they act as pollution magnets that marine animals mistake for food, and which can eventually end up in our food.
The Guppyfriend Washing Bag is a patented solution that filters out microfibers released from synthetic materials during washing. The self-cleaning fabric bag is made of a Polyamide 6.6, micro-filter material.