It depends on how badly you want to get rid of those parts. You could look up the parts list of different appliances and build them and then sell the appliances that would get rid of the parts but you're going to pay more more for the appliance then you will get when you sell it. I only mentioned this way because I know there are people with OCD who would love to see those items gone so they can have a cleaner look on their parts list .
In the future you should just decline those gifts that you do not need. You only get 20 gifts so you should make them count. If you decline it does not count against you and it allows someone else to give you what you actually want or need. I put on my wall what parts I do need or I will have the appliance that I am building and its parts. If you let your neighbors know what you need they will be able to choose the right parts. When your neighbors know what to give to you you will become an easy neighbor to work with and you will probably see more traffic and your gifts will max out quicker.