I would like to try making some chutneys/cranberry sauce for gifts for Xmas this year (I know it's only October, but trying to be prepared!) and was just going to use some jam jars with screw-on lids (unused) that I have knocking about. But after doing some googling I'm feeling a little lost and not sure if these will be ok or not, as I have found some sites that say they won't form a good enough seal and that you have to use the two-piece lids with the flat tops and rings. If it was just for us I wouldn't be so worried but as they are for gifts I wouldn't want to risk them going mouldy, but I also don't want to spend the extra money on more expensive jars if I don't need to! Does anyone know if wax discs and normal screw-on lids with a safety button are sufficient? Also, do I need to boil them in a water bath once I have put the lids on, or just fill the jars whilst warm? TIA. 