Manual lawn aerators do in fact work.
I know this because I’ve used them multiple times in the past.
Over the years, I’ve seen lawn care enthusiasts debating whether these kinds of tools have any positive effect on soil compaction.
Some have even claimed that they compress the soil downward and make the issue worse.
However, this does not seem to be the case.
In October of 2021, I decided to do a little experiment.
To make a long story short, I chose a small section of an untreated lawn and proceeded to use a manual “hollow tine” aerator on it.
Six months later, I realized that the grass in this 1 x 3 ft. spot was looking much healthier than the rest of the lawn.

The red square highlights the area that I chose. As Spring crept in, I started to notice that this section of the lawn was growing much thicker and greener.
As you can see, there is a huge difference between the spot that I used the manual aerator on and the surrounding lawn.
In this case, I used the “Draper 30565 Lawn Aerator” (pictured). However, most hollow tine aerators look similar and work pretty much the same.
Note that this tool did not remove any soil plugs from the lawn.
Unfortunately, the metal tubes in these things tend to become clogged with soil after a very short period of time. Especially if the soil is damp.
Although you can remove the soil with a screwdriver, there is little point in doing so. From my experience, it doesn’t matter if the tubes are clear or not. It still won’t pull up any plugs.
However, despite this, it still managed to do a very good job.
After doing this experiment and seeing the results, I find it difficult to arrive at any other conclusion.
Yes, manual aerators work.
Well, at least the “hollow tine” ones do.