INFO: Have you communicated your definition of clean or just said "we need to be cleaner?" Also, have you discussed a "working arrangement" for your dishes/appliances in the kitchen?

Those are some important things to get out explicitly, and it sounds like you are all relatively young, so probably not much experience with past shared living situation. For some people, having the dishes soaking and doing them within 12 hours is clean, others want the kitchen clean between meal ready and eating. Should you establish a fixed cleaning schedule where you all set aside 30 mins to tidy up? Different things work for different people.

Appliances like the espresso machine are tough, and you should be clear why the grounds need to be removed immediately - on something like a traditional coffee brewer, mold is not that much of an issue versus a specialty appliance.