Usually, the interior parts of shoes are made of leather and subject to important strain: rubbing and perspiration in particular.  Therefore regular care is important :
Our Protective Oil Saphir HP Spray is the most efficient for this task.
This very fluid high protection oil is intended for the regular care of shoe interiors which are difficult of access. It nourishes and waterproofs, and regular use will help keep the interior linings in good condition, without the risk of discharge on feet or socks