I reuse items in the kitchen that I used for soaping all the time.
While the whole lye-thing is scary and dangerous, it's not an everlasting demon that lurks on your tools or containers if they've been properly washed.
Think about it: Lye losess its potency the minute you open the container. That's why lye must be kept in a sealed container. Lye cannot linger on containers indefinitely to zap you when you're most vulnerable. It has a shelf life -- and it dissolves in water.
Once you've saponified your oils, lye has been converted to a soap molecule... meaning there is no lye in your ingredients any more (unless you've somehow didn't fully dissolve your lye in wanter and then created lye pockets). So your stuff now has soap on it.
As long as your utensils and containers are thoroughly cleaned and allowed to sit in open air, there's no reason for them not to be safe. After all, you wash them with soap and then cook with them, right? Are you afraid of there being soap in your food?