Dump valves '95 Excella 1000
In our continuing preparations to use the barn-find our new-to-us '95 Excella 1000, Lucy3 aka L3, we again are asking for recommendations/suggestions. We understand from the PO this TT was parked in a shed for the past 10-12 years. So far, the furnace works, the A/C works, the frig works, the LP tanks are full and re-certified and tomorrow the wheel bearings will be checked then tires. However, since the waste tanks have not been used in 10-12 years, are there any specific preparations needed before using the dump valves on the main and auxilliary holding tanks?
Thanks in advance.