You can use an "all-in-one" type product (available at Decathlon stores) to unjam, clean, lubricate and protect your child's bike. It's a very handy product!To lubricate the chain, turn the pedal and "spray" the product all the way along. Then leave it to dry for a few minutes. If the chain is very dirty, clean it with a brush or a cloth and spray it again with "all-in-one" product. Our tip: Avoid any contact with the brake pads and the braking area on the wheel rims. Protect your bike: Apply all-in-one regularly to prevent rust from appearing.