diff --git a/.gitignore b/.gitignore
index a9d73c8..304a0c8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1 @@
-settings.conf
\ No newline at end of file
+settings.conf
diff --git a/README.md b/README.md
index 5175b3d..2c27582 100755
--- a/README.md
+++ b/README.md
@@ -68,13 +68,13 @@ Lastly, if the asset_tag field is blank in JAMF when it is being created in Snip
 4. Install dependencies
   - `pip install -r /path/to/jamf2snipe/requirements.txt`
 
-5. Configure settings.conf
+5. Copy settings.conf.example to settings.conf and configure
 6. Run `python jamf2snipe` & profit
 
 ### Linux
 
 1. Copy the files to your system (recommend installing to /opt/jamf2snipe/* ). Make sure you meet all the system requirements.
-2. Edit the settings.conf to match your current environment. The script will look for a valid settings.conf in /opt/jamf2snipe/settings.conf, /etc/jamf2snipe/settings.conf, or in the current folder (in that order): so either copy the file to one of those locations, or be sure that the user running the program is in the same folder as the settings.conf.
+2. Copy settings.conf.example to settings.conf. Edit settings.conf to match your current environment. The script will look for a valid settings.conf in /opt/jamf2snipe/settings.conf, /etc/jamf2snipe/settings.conf, or in the current folder (in that order): so either copy the file to one of those locations, or be sure that the user running the program is in the same folder as the settings.conf.
 
 ## Configuration - settings.conf:
 
@@ -117,6 +117,16 @@ Some example API mappings can be found below:
 
 More information can be found in the ./jamf2snipe file about associations and [valid subsets](https://github.com/ParadoxGuitarist/jamf2snipe/blob/master/jamf2snipe#L33).
 
+### Environment variables
+
+Config values can be set through environment variables, e.g.:
+```
+[jamf]
+url = $JAMF_URL
+username = $JAMF_USERNAME
+password = $JAMF_PASSWORD
+```
+
 ## Testing
 
 It is *always* a good idea to create a test environment to ensure everything works as expected before running anything in production.
diff --git a/jamf2snipe b/jamf2snipe
index 03c9912..a552445 100755
--- a/jamf2snipe
+++ b/jamf2snipe
@@ -52,6 +52,12 @@ import time
 import configparser
 import argparse
 import logging
+import os
+
+class EnvironmentInterpolation(configparser.BasicInterpolation):
+    def before_get(self, parser, section, option, value, defaults):
+        value = super().before_get(parser, section, option, value, defaults)
+        return os.path.expandvars(value)
 
 # Set us up for using runtime arguments by defining them.
 runtimeargs = argparse.ArgumentParser()
@@ -86,7 +92,7 @@ if user_args.dryrun:
 
 # Find a valid settings.conf file.
 logging.info("Searching for a valid settings.conf file.")
-config = configparser.ConfigParser()
+config = configparser.ConfigParser(interpolation=EnvironmentInterpolation())
 logging.debug("Checking for a settings.conf in /opt/jamf2snipe ...")
 config.read("/opt/jamf2snipe/settings.conf")
 if 'snipe-it' not in set(config):
@@ -444,6 +450,10 @@ def update_snipe_asset(snipe_id, payload):
         logging.debug("Got back status code: 200 - Checking the payload updated properly: If you error here it's because you configure the API mapping right.")
         jsonresponse = response.json()
         for key in payload:
+            if key == 'purchase_date':
+                payload[key] = payload[key] + " 00:00:00"
+            if payload[key] is '':
+                payload[key] = None
             if jsonresponse['payload'][key] != payload[key]:
                 logging.warning('Unable to update ID: {}. We failed to update the {} field with "{}"'.format(snipe_id, key, payload[key]))
                 goodupdate = False
@@ -472,6 +482,9 @@ def checkin_snipe_asset(asset_id):
 # Function that checks out an asset in snipe
 def checkout_snipe_asset(user, asset_id, checked_out_user=None):
     logging.debug('Asset {} is being checked out to {}'.format(user, asset_id))
+    if user == '':
+        logging.info("Checking in {}".format(asset_id))
+        return checkin_snipe_asset(asset_id)
     user_id = get_snipe_user_id(user)
     if user_id == 'NotFound':
         logging.info("User {} not found".format(user))
@@ -511,11 +524,13 @@ logging.info("SSL Verification is set to: {}".format(user_args.do_not_verify_ssl
 logging.info("Running tests to see if hosts are up.")
 try:
     SNIPE_UP = True if requests.get(snipe_base, verify=user_args.do_not_verify_ssl, hooks={'response': request_handler}).status_code is 200 else False
-except:
+except Exception as e:
+    logging.exception(e)
     SNIPE_UP = False
 try:
     JAMF_UP = True if requests.get(jamfpro_base, verify=user_args.do_not_verify_ssl, hooks={'response': request_handler}).status_code in (200, 401) else False
-except:
+except Exception as e:
+    logging.exception(e)
     JAMF_UP = False
 
 if SNIPE_UP is False:
@@ -747,7 +762,7 @@ for jamf_type in jamf_types:
             # The user arg below is set to false if it's called, so this would fail if the user called it. 
             if (jamf['general']['asset_tag'] != snipe['rows'][0]['asset_tag']) and user_args.do_not_update_jamf :
                 logging.info("JAMF doesn't have the same asset tag as SNIPE so we'll update it because it should be authoritative.")
-                if snipe['rows'][0]['asset_tag'][0].isdigit():
+                if snipe['rows'][0]['asset_tag'][0]:
                     if jamf_type == 'computers':
                        update_jamf_asset_tag("{}".format(jamf['general']['id']), '{}'.format(snipe['rows'][0]['asset_tag']))
                        logging.info("Device is a computer, updating computer record")
diff --git a/settings.conf b/settings.conf.example
similarity index 62%
rename from settings.conf
rename to settings.conf.example
index 5a0ce68..1aa67be 100644
--- a/settings.conf
+++ b/settings.conf.example
@@ -4,17 +4,17 @@ username = a-valid-username
 password = a-valid-password
 
 [snipe-it]
-#Required
+# Required
 url = http://FQDN.your.snipe.instance.com
 apikey = YOUR-API-KEY-HERE
 manufacturer_id = 2
-defaultStatus = 2 
+defaultStatus = 2
 computer_model_category_id = 2
 mobile_model_category_id = 3
-#Not Required, uncomment to use
-#computer_custom_fieldset_id = 3 
-#mobile_custom_fieldset_id = 4 
-#asset_tag = general serial_number # If not specified, defaults to jamf-{id} or jamf-m-{id}
+# Not Required, uncomment to use
+# computer_custom_fieldset_id = 3
+# mobile_custom_fieldset_id = 4
+# asset_tag = general serial_number # If not specified, defaults to jamf-{id} or jamf-m-{id}
 
 [computers-api-mapping]
 name = general name
@@ -22,8 +22,8 @@ _snipeit_mac_address_1 = general mac_address
 
 
 [mobile_devices-api-mapping]
-_snipeit_imei_4	= network imei
+_snipeit_imei_4 = network imei
 name = general name
 
 [user-mapping] # The field from jamf that you want to search Snipe with
-jamf_api_field = location username
\ No newline at end of file
+jamf_api_field = location username