You could spray a mixture of 4 parts water and 1 part methylated spirits on the seat and monorail and wipe over with a paper towel to disinfect the surfaces.
The seat must slide smooth on the track. Sometimes after use you will see black spots on the monorail and the white rollers. It is residues from the rollers and the stainless steel track mixed with sweat. If not removed these black spots will build up and feel like bumps on the monorail when rowing.
Use the same spray mixture to remove the spots. Wipe over with a cloth or non-abrasive scouring pad. Be careful not to get your fingers between the seat rollers and the monorail track.
If the seat surface gets very dirty try to apply a mild solid hand soap with your hands. Let is rest a minute and wipe over with a damp cloth to remove the soap. Now the non-slip surface should be as new.