Idopher question and basic yeast washing question

Two short questions:

1. A fellow brewer recently returned a 5 gallon keg that he had cleaned and then sanitized with an idopher solution. The keg is about 3/4 full of this solution and I have never used idopher below so I am unsure if I just dump the sanitizer out and then use the keg or do I need to do several final rinses before using the keg? The solution has been in the keg for 2 weeks. I have only been using Starsan for my brewing.

2. Made my first attemp at yeast washing 2 weeks ago and I was able to collect 3 pint jars with white yeast sediment on the bottom. I know I should make a starter from the sediment a few days prior to brewing but what I don't know is what signs should I be looking for that will show me that the washed yeast is viable?

Thanks for any input.

iodophor is a no rinse but you can starsan it again if you don't trust it

i would recommended making a starter

Thanks for the feedback. I may not have been direct in my second question. What I would like to know is what physical signs I should look for once I have made the starter that the washed yeast is viable? I wonder if I should just look for more yeast sediment occurring or are there other signs to look for that will show you your yeast starter is viable and healthy?

Thanks.