Never actually tried this but I've heard it works. Take a spray bottle fill it with soapy water and a good dose of hot sauce. Spray whatever the deer are eating. The soap will leave a film even after the water dries. When they nibble the sprayed plant or veggie the hotsauce burns their mouth and they stop. After a while they learn not to fool with it. Of course you will need to wash off any edible fruit or vegetable you harvest to prevent giving yourself the same treatment but heck you should be washing all of it anyway.