It is important to ensure the seat rails in your car are kept free from any obstructions, clean and lubricated in order to allow the seats to operate properly and move freely. It is very easy and fairly common for coins, sticky sweets and pens etc to get dropped down the side of seats and become lodged in the seat rails.
You should pay attention to the seat rails whenever you clean the rest of the interior. When vacuuming the rear of your car, pull the seats fully forward and remove any loose items from under the seat and from in and around the seat rails. Once any loose and larger items have been removed by hand you should use a vacuum cleaner with a crevice tool attachment to vacuum out the inside of the seat rails. If there are any stubborn items like sticky sweets stuck in the rails you should use a diluted all purpose cleaner and a stiff bristled detailing brush to loosen and clean up the affected area.
Once all objects and obstructions have been removed and seat rails cleaned they can then be lubricated with an appropriate product. Out of the factory, a cars seat rails are lubricated using an appropriate silicone grease product, however any spray, light oil or grease lubricating product can be used, just be sure to avoid getting any of the product onto surrounding upholstery and trim. Once you have cleaned and lubricated the rear section of the seat rails you should push the seat back fully and repeat the process for the front section.