In my little brick bungalow in a midwest US city, I've got an old
style (~1954) venetian blind measuring about 8' wide and 6' tall,
and with many years encrusted grime. Seems to be made of metal,
maybe aluminum.

I can't figure how to clean it. It's too big for the bathtub. I
can't find a space on an exterior wall with ready water supply
to clean it outside.

It costs about $60 to have it cleaned if I drop it off. Another
$65 if they pick it up.

Do they have reasonably priced plastic blinds to replace such
large blinds? I tried HD web site, couldn't even find sizes
listed (dunno why).

Any info, suggestions etc much appreciated.

Will