How to Clean and Maintain an Original Prusa MK4S

Step-by-step instructions

Step 1: Clear the print area and inspect cold

Finish the print, unload filament when required, and allow the printer to reach room temperature. Remove the flexible sheet and loose printed objects. Inspect the frame, cables, fans, rods, belts, and hotend before power is disconnected so any displayed temperature or error is recorded. Then switch off and unplug the MK4S for all routine dry cleaning and lubrication.

Step 2: Remove loose filament and dust

Prusa recommends keeping the printer free of scraps around moving parts and beneath the heatbed. Use a soft brush, small broom, or controlled vacuum to collect filament pieces, dust, and broken support material. Do not pull on wiring bundles, remove fasteners by suction, or blow grit into bearings and electronics with high-pressure air.

Step 3: Clean the nozzle and heaterblock at the prescribed heat

Prusa directs owners to heat the nozzle to 250°C for about three to five minutes so bonded filament softens. With the printer stable and supervised, use a small brass brush on the nozzle and heaterblock exterior. Avoid every hotend cable, because a conductive brush can cause a short. Switch off afterward and wait about ten minutes, checking the displayed temperature before touching nearby parts.

Step 4: Clean the Nextruder drive and sensor path

Open only the user-serviceable Nextruder access described by Prusa. Remove ground filament from drive-gear grooves with a dry brush and rotate the gear through its normal access range. Cover an open PTFE path so debris cannot fall into it. Clean the filament-sensor path using Prusa's dedicated method rather than pushing a metal tool toward the electronics.

Step 5: Wipe smooth rods and check bearings

Use a clean paper towel or lint-free cloth on the X and Y smooth rods to remove dust and dirty lubricant. Inspect for scratches, corrosion, or a dry bearing sound. Apply Prusa lubricant only in the amount and locations specified for MK4S linear bearings, then move the axis through the approved range to distribute it. Do not coat belts or motor pulleys.

Step 6: Clean and lubricate Z components correctly

Wipe the Z lead screws and smooth rods according to Prusa's component map. Apply lubricant only where the current MK4S article directs; a threaded lead screw and a smooth rod may have different requirements. Remove excess that could sling onto the sheet or frame. Never use a general penetrating spray in place of Prusa's named lubricant.

Step 7: Inspect belts, pulleys, and fasteners

Brush dust from belt teeth and pulley edges without applying liquid or lubricant. Check belt tension using Prusa's approved method and examine pulleys for trapped filament. Do not change tension solely because a belt looks dusty. With the printer cold and off, check the Nextruder hotend thumb screws by hand as Prusa directs and confirm the hotend does not move sideways.

Step 8: Clean fans and electronics dry

Hold fan blades stationary and lift dust from grilles and accessible blades with a soft brush. Use gentle suction from a distance rather than spinning the fan. Brush dust from the electronics enclosure vents without opening energized components. Do not use a damp cloth, air compressor, or metal tool around circuit boards and connectors.

Step 9: Clean the flexible steel sheet

Identify whether the installed sheet is smooth, textured, satin, or another Prusa type and use its exact surface-preparation instructions. Clean while cold, handle by the edges, and avoid transferring lubricant from maintenance gloves. Dry both sides and wipe the magnetic heatbed before reseating the sheet so no particle creates a raised spot.

Step 10: Reassemble and run checks

Remove all cleaning tools and protective swabs, close Nextruder and electronics covers, reinstall the dry sheet, and reconnect power. Home the axes and listen for friction, belt noise, or fan contact. Confirm the hotend temperature reads normally, then run a first-layer calibration or small test print before a long job.