You do not wipe your microwave.
Do you hate cleaning your microwave? There is a reason for that. Dry and encrusted food is difficult to remove.
The solution is simple; Wipe off spilled product immediately.
If it is too late, heat a bowl of water in the microwave for a few minutes until it is steamy, let it cool for a few minutes, and wipe the interior carefully. The steam helps to loosen bonded gunkers.