How to delete or clear index in Solr
There two indexing strategy: incremental or reindexing all documents. For small dataset or testing, reindex all document when needed is a common use case, if you have a large dataset, you may need to add new data to index each time.
It's very useful when you are explorer Solr, you change make some changes to configuration files and reindex the documents.
Looks like the GUI didn't provide the delete feature. You have to use curl command.
Execute the following command
curl http://localhost:8983/solr/db/update?commit=true -d "<delete><query>*:*</query></delete>"
If you don't know what URL to use, first do a simple query in Solr ADMIN panel, on the top of the result will be the URL that generate the search results for example
You need to change the select command to update, the URL before the command is the same.