Unfortunately, with Continental, your options are extremely limited.
With purchasing merchandise, from what I remember, it can only get you up to 50% of the purchase price of something (which is usually valued at list price).
That is enough for a free ticket. Perhaps a nice weekend somewhere.
Another nice gesture would be to donate miles to charity and see if there is a value you can assign to a tax deduction. Helping yourself and someone else. You didn't mention when the last time you had activity on your account, but keep in mind that Continental has the option of closing an account if there is no activity in the last 18 months.

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NW Worldperks Plat
HHonors Diamond
Priority Club Platinum
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