I now use a Neilmed `squeezy ' saline rinse bottle, as it is more reliable than their battery powered pumps. Generally 1 teaspoon of salt - neti pot type - is added to 8 fl oz of previously boiled and cooled water. Use about one hour before bed time, to allow your nasal passages to drain, before putting on your mask. Do squeeze the bottle gently though, as you don't want to cause other damage to your nasal passages.
Generally, oxymetazoline or similar decongestants are frowned on by the medics as rebound congestion can apparently occur if continued for more than a few days.
Now the disclaimer - I am not a Medic, so please use this information at your own risk.