Vintage Gray, Taupe, & Cream Agate Geod From Native American Shop/New Mexico

I purchased this on tribal land, in a Native American rocks and mineral shop in New Mexico, sometime around 2002. This is a large slice of geode with various natural stripes. I've had it in my garden or storage box all this time, and it needs to be cleaned, but I didn't know what to use, so I'll leave that up to the buyer. It weighs 1 lb 7.5 Oz Width-5.5" Height-4" Around-13" Width around Condition- just need to light cleaning but I don't see any issues