Don't forget to clean your nozzle occasionally.

[Mark_Durbin]

Don’t forget to clean your nozzle occasionally.
Use this excellent guide from @Whosa_whatsis :
http://bukobot.com/nozzle-cleaning

[Alexandr_Redkin]

я просто прокаливаю наконечник и пока раскаленный, брызгаю WD. зачем всё усложнять?

[Kenneth_Cummings]

worked for me