If you lost the water container for a steam vac silver Hoover what would work

I doubt you would satisfactorily be able to jury-rig a container suitable to replace the solution water tank (or dirty water tank as the case may be). I feel your best bet is to order a new replacment tank directly from Hoover. Probably run around $40.

First find your model number off the machine. Then go to

--- It's also possible you could find a repacment on ebay. I did a quick search and found both types of tanks for just a little over $20 (inc. shipping).

solution tank:

waste water tank:

general search brings up these results: