Jan, Can you remove the jets from the spray bars? If you can take these out and clean them up separately whilst pumping round a descaling solution there will be no jets blocking. You can then change the descale solution daily and hopefully the scale will have dissolved and been washed away before the jets are replaced. We use citric acid to descale our stainless steel resist stripper - but our problem is hard water scale ( calcium and magnesium ) causing tin to drop out as calcium ( or Mg ) stannate. Good Luck ! Leon Snowdon ############################################################## TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c ############################################################## To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TECHNET <your full name> To unsubscribe: SIGNOFF TECHNET ############################################################## Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################