“How many times a day should I clean my dentures?”

at least 2

It's wise to clean them like you would your natural teeth, after meals, snacks, and at bedtime. Although you can no longer get decay or gum disease, the cleaner your dentures are, the less likely you'll get things like oral fungal infections, etc. Another thing to consider is leaving your dentures out at night to allow all the tissues in your mouth to recover from the pressure of the denture.

After eating. Just like brushing your teeth.