Manage Service Cashes
After several hours of flying with Tileproxy the cache folder can end up with 10s of Gigabytes of tiles. Not a problem in itself but for obvious reasons it's advisable to keep an eye on this.
In the Tileproxy menu click Manage Service Cashes. Depending on the size of the cache and the speed of the disk/system it can take as much as several minutes for the map to appear. Do not be tempted to click again! Doing so will load it twice and double the time.
Once the map appears it is quite straight forward. Drag a selection box around an area which you wish to erase.