Start by replacing the Print head with an all metal hot end like the Micro-swiss
Then adjust the retraction settings in Cura to prevent strings in the print as follows:
Enable Retraction: Yes
Retraction Distance: Begin with a setting of 5 mm and adjust it up or down by 1 mm until all stringing is gone.
Retraction Speed: Begin with 50 mm/s and slow down if you are seeing filament damage.
Retraction Extra Prime Amount: Leave at 0
Maximum Retraction Count: Set to 10 and only adjust if you see filament damage.
Minimum Extrusion Distance Window: Set to your Retraction Distance
Nozzle Switch Retraction Distance: 16 mm
Nozzle Switch Retraction Speed: 20 mm/s
Limit Support Retractions: Enable