Why is the silicon mold oily?

The molding silicone rubber itself doesn’t contain any oil, so it won’t be oily. If the mold is oily, it may be because of two resons:

1. you add the compound silicone oil( the compound of silicon oil and white oil). The white oil is not silicon oil but a kind of petrochemicals.

2. Your supplier add to much silicone oil when they producing silicone rubber or reducing the hardness of silicone rubber.