Try boiling a kettle, filling a bowl of water, pop it in the oven on 100 for 30 minutes. That will soften it up. Then you could also try a paste of bicarbonate and water painted on and leave for a while. It might take several goes.
When it’s done, buy a silicone liner for the bottom and wipe out the sides and roof with soapy water every time you use it. It saves sooo much time in the long run.
Try boiling a kettle, filling a bowl of water, pop it in the oven on 100 for 30 minutes. That will soften it up. Then you could also try a paste of bicarbonate and water painted on and leave for a while. It might take several goes.
When it’s done, buy a silicone liner for the bottom and wipe out the sides and roof with soapy water every time you use it. It saves sooo much time in the long run.
Good luck!