Can you back flush in some way? Not sure what you could use to fasten a hose to that drain valve. Water or air would be worth a try. A small diameter hose off an air compressor?
Vasaline would help any binding, not sure you have that problem. Next would be how to get it into the valve.
I assume you have a 2009? I think this issue will strike many of us, as those plastice valves have a limited life span. Brass would be better.
Is there an access panel on the Escape tanks? If not, it may be necessary to cut one.
Paul and Janet Braun
2003 Toyota 4Runner V8 now 2012 Toyota Sequoia V8
Escape 19' 2010 now 2014 Escape 21'