chevy 250 oil drainage Q's from head

[thejed72]

Went to replace my leaky valve cover gasket today and found my oil draiange holes plugged up and my head caked with oil. cleaned the clumped old oil out, and found my drain holes which were packed. Obviously this engine has seen better days, but for the time being, can I run a copper wire down the drainage holes without doing any damage? I know dropping the pan is next, as is cleaning/replacing the oil pump, filter, and oil change, But a rebuild is not in the budget right now. Pushrods I'm sure could use a good cleaning too, but any other advice as to how I can keep this thing going and getting the gunk buildup with the motor in the truck gone or at least better, I'll take whatever tips I can get.