Don't worry - essentially everyone (myself definitely included!) makes some minor mistakes as they learn to map.

There's two approaches you could take to find the waste baskets you previously mapped as nodes on sidewalks:

By Overpass: Overpass Turbo (or Ultra) is a very powerful tool and a query like this should help:

https://overpass-turbo.eu/s/1V1z
Click "Run" at the top left and wait (it will take a bit!)
I did my best to annotate and explain what each line does. (I'm not a software dev)

By changesets: OSMCha is a great resource and a query like this may help you find those earlier changesets:

https://osmcha.org/filters?aoi=914b9552-813c-4360-baa2-5a6a8c211759

Do let me know if you need any further help or have any additional questions. :)