Repairing two spots on the entrance floor

Hello everyone! There are two stains on the floor caused by Plumbo rørvask and they need to be fixed. The two spots are not big, but i want to fix them because the owner is going to sell the apartment. i would like to get soeme help to repair it, and i hope that the offer includes: the depth of the damage. How to repair it and the cost. Have a nice day Greetings, Ghaeth