List<string> outlist = new List<string> { "SourceList1", "SourceList2", "SourceList3", "SourceList4", "SourceList5",
"SourceList6", "SourceList7", "SourceList8", "SourceList9", "SourceList10" }; // прописываешь свои списки
foreach (string str in outlist) {
project.Lists[""+str+""].Clear();
}