You can try a blower. If that doesn’t work, you’ll need the full sensor cleaning kit.
Giottos Rocket Blaster Dust-Removal Tool (Medium, Black) AA1910
VSGO MILC Mirrorless M43 (CCD/CMOS) Panasonic Olympus Digital Camera Sensor Swab DDR-12 (Box of 12 X 12mm Swab + 15ml Sensor Cleaner)...