archivelogs scheduling

I inherited a system that I only want for there to be 7 days of archivelogs kept on the server. The rest should be backed up and removed by RMAN. Right now there seems to be several weeks worth of archivelogs and I am not sure what the schedule is for them. I looked at the script and it doesn't seem to indicate how the logs are being removed or what the settings are. Where else should I look? Is there a parameter that needs to be alter to be 7 instead?

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