The high humidity in the atmosphere on damp, rainy or foggy days can increase the risk of serious felting and catch out even experienced staff.
Animal hair textiles have a huge capacity to hold moisture and even at normal atmospheric humidity they can hold 15% moisture. Under normal circumstances, animal hair textiles can be safely drycleaned with a moisture content of 15 – 16%.
Unfortunately, these textiles can hold up to 28% moisture before they begin to feel noticeably damp and when the atmospheric humidity is very high, the regains of pure wool and other animal hair textiles may be well above 16%. If they are drycleaned in these conditions the risk of felting/milling shrinkage will increase progressively as the moisture content rises.
So cleaners should avoid processing animal hair textiles on short service times in damp weather. In such conditions, garments made from these textiles should be hung for several hours (or preferably overnight) to recover their normal moisture content before being drycleaned.
Fine high quality textiles are mainly at risk, such as those found in cashmere coats, high value garments in general and particularly angora garments. Roger Cawood