Locate the screw at the back of the Franke faucet’s spout body. Shine a flashlight on the back of the spout body if you have trouble locating the screw, as the screw may sit in a small hole, making it hard to spot.
Insert a 2-millimeter screwdriver into the spout’s anchor screw. Turn the screw counterclockwise until the spout becomes loose and you can slide it off the faucet assembly. If the screw does not turn easily, spray penetrating lubricant around it, and allow the lubricant to soak in for five minutes before turning the screw again.
Flush the plastic flow restrictor in the rear part of the spout, using a strong stream of water. Dislodge any leftover debris in the flow restrictor with a flat-head screwdriver blade. Slide the spout back on the faucet and tighten the anchor screw by turning it clockwise.
Wrap duct tape around the jaws of a pair of channel locks, then clamp the channel locks to the aerator. Turn the aerator’s body counterclockwise with the channel locks. Flush the aerator screen with fresh water to remove the sediment buildup, then replace the aerator the same way you removed it.
Restore the water to the faucet by turning the water supply valves under the sink counterclockwise until the handles stop, opening the valves all the way. Use only your hands to turn the handles, as tools may damage or break the valves.