Q: Haw to clear app store purchases???

I think this Apple doc has the info you're looking for -> iTunes Store: Hiding and unhiding purchases

To hide your purchases

 

1. Depending on the content type, open the App Store, iBooks, or iTunes Store application on your device.
2. Tap Purchased from from the bottom navigation bar.
3. Locate and swipe left or right on the item would like to hide; this displays the Hide button.
4. Tap the Hide button.