Air is about 20 percent oxygen and 80 percent nitrogen. Absorbers remove only the oxygen. The air left in the container is mostly nitrogen and will not affect the food or allow the growth of insects. Therefore, the final packaging may not have the appearance of being " vacuum-packed " because of the remaining nitrogen in the package. The only way to get a good vacuum seal inside the bag is to use a vacuum sealer.
Oxygen absorber packs are not reusable. Once the plastic pack that holds the absorbers is opened, they will need to be utilized for your storage absorber needs or they will simply absorb all oxygen around them (which if not in a closed container or bag, they will fill fully with oxygen around them and be used up).
The pink eye indicates the packs are free of oxygen. When the eye turns purple, the oxygen packs are used, this shows that they have absorbed fully with the surrounding oxygen or on their way.
Let us know if you have further questions, happy to help!