How can I delete messages from a SOW topic?

There are several ways to do this, depending on your needs.

Timed expiration. If your application can predict that a specific record, or set of records, is only valid for a certain period of time, you can use SOW expiration to automatically remove messages that are no longer valid.
Application message cleanup. If an event in your application, such as completing an order, indicates that the record is no longer valid, you can use the sow_delete_by_data method to delete the message from AMPS.
Action configuration. You can create an action that deletes messages from the SOW. The action can be configured to run on a periodic schedule, or in response to a signal or event.
Administrative cleanup. You can also use the spark command line client application to delete messages from the sow, as shown below. This runs a sow_delete command from the spark client.

Delete all messages from a SOW topic
```
$ ./spark sow_delete -proto amps -type <the-type> \
               -server localhost:9003\
               -topic Trades -filter '1=1' \`\`\`
```
Delete all messages that match a filter from a SOW topic
```
$ ./spark sow_delete -proto amps -type <the-type> \
               -server localhost:9003\
               -topic Trades -filter "/55 = 'Transport.123'" 
```
Notice that if you do not provide a filter, spark will perform a SOW delete by data, and wait for messages (one per line) to use as the data for the delete.