Marmosets can be trained, and the training is very simple, such as training marmosets to go to the toilet in a designated place.

First of all, you first observe where it usually goes to the toilet and put some sawdust there , and then put the urinal you prepared on the sawdust it wets, and mix it up. Then put the marmoset there and let it smell, so it learns to go to the toilet at a certain point.