Kenny, I assume you mean de-scaling! Citric acid is okay as is Ascetic just let it do its stuff and wash out well afterwards. I know of one model engineer who treats his feed water by adding a tea spoon of Ascetic acid to every tender full of water. Never tried it myself but the M.E. in question swears by it. His exhaust steam stinks a bit though. Regards, IDP "Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, Champagne in one hand - strawberries in the other, body thoroughly used up, totally worn out and screaming WOO HOO - What a Ride!" "Never drive faster than your gaurdian angel can fly" Priest & Sons Model Engineers http://www.kinvermes.pwp.blueyonder.co.uk/p1.htm ----- Original Message ----- From: <kenny.macdougall@xxxxxxxxxxxxxx> To: <modeleng@xxxxxxxxxxxxx> Sent: Tuesday, December 05, 2006 7:42 PM Subject: [modeleng] Boiler descaling Hi All what would you recommend for boiler decaling kenny MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.430 / Virus Database: 268.15.7/569 - Release Date: 05/12/2006 03:00 MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.