Your best tactic regarding reactivation efforts is email marketing. It's virtually free and you control everything.
If you are simply executing your typical email blasts (same email to every customer five times per week), you are undoubtedly getting benefit, as shown below.
Yeah, look at those email subscribers! Especially look at those with 1 click-through in the past year or 2+ click-throughs in the past year. That's where you get a big bump in reactivation, and a huge increase in profitability.
The best reactivation marketers have programs tailored to the audience they hope to reactivate. This is a place where "engagement" actually means something. Take advantage of this opportunity!!