A piston stuck after long storage is usually cleaned in an ultrasonic bath, possibly equipped with new seal and piston mechanism; a price of around 73 euros is appropriate for proper cleaning and standard servicing, since the workload is the larger cost share. A 'ultrasonic examination' in the medical sense does not exist on pens; what is meant is always the ultrasonic bath as a cleaning method. A list of trustworthy repair experts can be found on the forum (community-fountainpen.de). In general nibs are the most vulnerable component and on roughly 50-year-old writing instruments practically no longer obtainable as a spare part; bent nib tips should therefore be carefully adjusted by experienced workshops.