You can put the knives in your bin. It is advisable to ensure that they are packaged securely so as not to cause injury to any persons.
With the introduction of wheelie bins everything is done by machine so that likelihood of injury has been vastly reduced. However it is still advisable to package the knives securely just in case.
All metal knives can be taken to your local waste disposal site where there will be a skip for scrap metal.