Deleting Spikes
From Geospike DocWiki
You can delete a spike in one of two ways: Option 1: On the spike list, swipe your finger from right to left. Then hit delete Step 1
Step 2
This short cut can be used in many other iOS apps, such as Mail
Option 2: While viewing a spike, press the 'Edit' button. Then delete all of the 'Visit Times'. When you delete the last visit time, it will prompt you to delete the spike.