1. PH value, phenolic yellowing and color fastness of yarn (Should be tested and approved by the factory laboratory before mass production) .
2. Yarn that is easy to shed, pilling, and hooking (When cannot be improved, the yarn should be replaced, or some of them can be improved by mixing auxiliaries.
3. Yarns which are easily deformed and shrunk after home laundry (deformed clothes can be improved by changing knitting ways, and shrunk clothes can be improved by adjusting the washing methods) .
4. Easily broken lurex yarn (to adjust yarn’s humidity and knitting speed) .
5. Easily slanted yarn (the twist strength can be adjusted during yarn production) .
6. Yarns with weak color fastness and sensitive color (to improve the color fastness treatment in the process of yarn production, and do color fixing when washing in the factory) .
7. Yarn with higher wool contenting is too harsh, and chicken paw marks will happen by fine needle knitting (can improve the hand feeling by washing. Chicken paw marks can be improved by dry ironing before washing, then wet ironing after shake drying, finally ironing after bake drying) .