It is unlikely that a new treaty on cluster munitions would require any new expenditures for clearance on the part of Canada, even though it likely would have a provision about assistance with clearance. That's because Canada is already engaged in funding that kind of activity.
You don't distinguish between munitions. You don't go into a field and just remove anti-personnel mines because of an anti-personnel mine treaty; you go into the field and remove everything. Canada would just need to continue the activities that it's already engaged in with regard to clearance activities.