Found this useful little snippet of Gcode that can be added to the start of a print to make sure the nozzle is well primed and clean. Original post linked below.
Purge and nozzle wipe starting gcode
Posted by carlos, 2 September 2015 2:01 pm
Use this gcode to purge and wipe filiment before printing.
Simplified version
M107 ;turn off fan
G28 X0 Y0 Z0 ;home X, Y and Z axis end-stops
G29 ;initiate z-probing
G1 X0 Y0 Z.10 ;move to corner of bed
G92 E0 ;zero the extruded length
G1 F200 E3 ;extrude 3mm of feed stock
G92 E0 ;zero the extruded length
Advanced wipe and purge
M107 ;turn off fan
G28 X0 Y0 Z0 ; home X, Y and Z axis end-stops
G29 ; initiate z-probing
G0 X0 Y0 F9000 ; Go to front
G0 Z0.15 ; Drop to bed
G92 E0 ; zero the extruded length
G1 X40 E25 F500 ; Extrude 25mm of filament in a 4cm line
G92 E0 ; zero the extruded length
G1 E-1 F500 ; Retract a little
G1 X80 F4000 ; Quickly wipe away from the filament line
G1 Z0.3 ; Raise and begin printing.