On the Base Toys Lodekka, the radiator grill is a separate fitting glued to the front of the bus. If you slide a single edged razor blade behind the grill, you can cut through the glue and GENTLY prise it off. This will reveal a small tab protruding through the front. The body shell is plastic and, again gently, you can insert a small screwdriver into the join between the body and chassis and lever the chassis out. There is another tab behind the rear number plate but this will also yield to gentle levering. You may find that the chassis will no longer clip in but it can always be glued back in. I usually use PVA for this as it is then easy to remove again if you need to,