How do you 'prove' a proving basket?

How do you 'prove' a proving basket?

Hi there guys, having mastered the art of sourdough, can anyone tell me how I can prevent my dough from sticking to the inside of my proving basket. I have tried flour mixed with semolina with mixed success but today I lost a great second prove due to the dough not turning out smoothly!!!!

Source: Fresh Loaf