Consumables are pretty simple records in ServiceNow based on what they are really used for. The best option would be to change the Model Category setup on the model and delete the consumables created as hardware assets. The reason is that there should not be much tied to these items or CI records so to save time that would be the easiest.
If that is not possible then you could look to script a copy of the consumables and change the sys_class_name to 'alm_hardware' and the model category to the correct type. The other key field to re evaluate is if they are "in stock" items you might need to split them out based on quantity since hardware assets are individual items.
