May I add these rubbers: https://www.amazon.com/-/de/dp/B01LYU5S6D/ref=sr_1_3?__mk_de_DE=%C3%85M%C3%85%C5%BD%C3%95%C3%91&keywords=faber+castell+rubber&qid=1581505299&sr=8-3
I gifted them to my gf and it helped for a while