Hello @Marcel_Brouillet, I am unaware of a way to remove them from the list, but you can make them less visible as outlined in @Bastien_Siebman 's post here. Keep in mind that the predictive list will always show the most recently visited projects first though.
If you have access to the advanced search feature, you can select Project for the “Type” and then specify archived for the “Status”. This will return a full list of archived projects that you can then go into and permanently delete, should you choose to do so.