By the Grace of the Gods: Volume 3

Ever since he left the forest, a boy from another world named Ryoma had been cared for by the duke's family. Rather than take advantage of their generosity, however, he's determined to live independently. Seeking to earn a stable income, he decides that alongside his adventuring job, he'll use his cleaner slimes to open a brand new laundromat! After he sets up his store by himself and hires some excellent employees, the laundromat opens to praise that far surpasses Ryoma's expectations. As business gets busier and more exciting, he also gets ahold of some new familiars in the third installment of this daily life fantasy!

[From J-Novel Club]