Vacuum-clean
It is important to first vacuum-clean backpacks and satchels. That way, you remove any crumbs and dust, ensuring you don't rub those in when you wash the bags afterwards.
Dap with a damp cloth
Next, mix some water and mild soap. Make sure the water is not too hot as this can cause colours to fade. Dab the mixture gently with a damp cloth. If the stains prove persistent, you can also use a soft brush (or toothbrush). Afterwards, rinse out the soap by dabbing with a damp cloth with clear water. Avoid using too much water.
Let it dry
Next, allow sufficient time to dry. Bags should be completely dry before you store them, to avoid mould.
Attention!
Unfortunately, most school satchels and backpacks should not be machine-washed. Always read their washing instructions carefully before putting them in a washer.