Rinsing out & reusing plastic (HDPE) containers

[Fluxor]

Along with a few chems bought from a supply house (a few oxidizers, a few acids, some salts), I've mostly been
finding many essential chems from local stores. Although it's taken some time and a few trips to get to know which stores
are likely to have stuff and which are likely not to, it's been highly rewarding in itself to locate stuff for my lab
from over the counter sources (Home Depot in my area is pretty lousy, while Lowe's is a lot better for a lot of stuff,
so is Ace Hardware).

Anyway, my problem is this: I want to reuse several plastic containers (HDPE) that originally held
herbal supplements. I've tried first washing them out with water and ordinary dishwashing soap.
I set them out to dry and then checked to see if they still had any lingering odor. They did.
Then I tried soaking them overnight in a solution of half water, half household bleach. Much to
my chagrin, they still had a lingering odor of the herbal supplements. Soaked them a 2nd time.
Same thing. A faint odor seems to persist. How crucial is it to get rid of any lingering odors from
the containers before I store the substances I want to store? (I want to store sodium carbonate,
sodium bicarbonate, corn starch, sugar, borax, epsom salts, and a few other salts that are easier
to store and handle in containers than in their original box).

I may be worrying over nothing, but I remember reading that no odors should remain when
reusing containers for one's lab.

Thank you for any help you can give me with this.

[thompson]

Usually, hot sudsy water does the trick. If it doesn't, a dilute solution of chlorine bleach usually does. If that doesn't work, you can try rinsing with a small amount of an organic solvent, followed by sudsy water. Any odor left after that is caused by such a tiny amount of the odorant that it's very unlikely to contaminate at any significant level whatever you store in the bottle.

The human senses of smell and taste are incredibly sensitive to some compounds, sometimes down to the parts per billion level. For typical bench reagents and so forth, it's not likely to be a problem.

Of course, you could just look for bottles that don't have an odor to start with.

[Fluxor]

Usually, hot sudsy water does the trick. If it doesn't, a dilute solution of chlorine bleach usually does. If that doesn't work, you can try rinsing with a small amount of an organic solvent, followed by sudsy water. Any odor left after that is caused by such a tiny amount of the odorant that it's very unlikely to contaminate at any significant level whatever you store in the bottle.

The human senses of smell and taste are incredibly sensitive to some compounds, sometimes down to the parts per billion level. For typical bench reagents and so forth, it's not likely to be a problem.

Thanks Robert, very helpful and informative. I did not take into account the great sensitivity of the
human sense of smell with regard to detecting many substances. Indeed, the ppb-level doesn't seem to be that
worrisome given the types of lab reagents I'll probably be working with in the near term.


I'll try about a 10:1 or 10:2 solution of water to bleach from now on for soaking. After reading your post, any greater concentration
seems to me to be wasteful of the bleach, without adding much effectiveness. I did not think of using an organic solvent. Will def. incorporate this
from here on out.

Of course, you could just look for bottles that don't have an odor to start with.

By way of passing along some info I've found useful as far as which containers have worked out well:
200 g/7 oz. clear glass jars for instant coffee (Nescafé, etc). I've found that these leave very little odorant
to begin with once empty of their coffee crystals, and leave no detectable lingering odor at all with just
a quick soak with dilute solution of chlorine bleach. Plus these jars are wide-mouth and the lids close
fairly tightly.