Ink Residue in Ogiva Demonstrator

[AZGecko]

HI folks,

 

I thought that filling my faceted Omas Ogiva demonstrator with Noodlers Kung Techeng was a good idea until... I emptied the pen and found that the ink had left the barrel stained and with ink residue. I flushed with pen flush with little to no effect. Right now, I have filled the pen with tap water.

 

Does anyone have any suggestions to at least clean out the residue and hopefully to remove the ink staining the barrel as well.

 

Thanks in advance