How to remove seeded contract close reasons lookup types

I'm looking for a solution for either disabling or end dating a seeded lookup for the contract close reasons lookup. The contract close reasons that are seeded will not be used by our client, and they would like to be able to remove these lookups as not to clog up the list or cause confusion to end users. Ideally we would like to end date or disable rather than change the meaning of the lookup code in the case of not prolonging this issue down the road if the client decides they no longer need the modified seeded lookup. Has