It is a very good idea to try to repair them because it is just as meritorious as creating new images or statues. The associated blessings are inconceivable.
If you can’t repair them then you can pass them on to people who can.
If you can’t find people who can make repairs, then you could put them up on altars and make offerings to them. For example, I heard of the story of someone who has a faded picture of the Buddha. He refused to dispose of it and put it up on the altar to make offerings to it. One day, he looked up and saw that the picture had restored itself. Similar responses can occur if we are sincere.
If you prefer to not put them on altars then you should put them away somewhere, in an area that is clean, until they naturally disintegrate. To intentionally destroy them is equivalent to shedding the Buddha’s blood, which should be avoided by any means.