When I got home I scrounged around and came up with a few jars that almost made their way into recycling... actually one was in the bin and I had Mark fish it out! Cleaning them is pretty easy as they are already reasonably clean before they are thrown into the recycling bin. Getting the labels off is a whole other story.
After soaking the jars in very hot water most of the day and having sticky residue left on the jars I went hunting on the internet. One person on a yahoo answers thread said that several cleaning products (that I don't own), WD40 or cooking oil cleans stubborn labels. Not wanting to use chemicals I opted to try the cooking oil method and was thoroughly surprised that it works!! The oil starts disolving the label glue straight away and turns into a creamy opaque gel. After working it in I used a butter knife to gently scrap the goop away then washed it thoroughly in soapy water.
Sparkling clean jar with label completely removed
So that is the cleaning taken care of, now for steralising.
Before using the jars for food they need to be steralised so that the food won't go bad in the sealed jars. Again I turned to the internet and looked through several sources until I found a general concensus. There are two methods for hot steralisation. I used the dry method which I thought would be safer than trying to keep them in hot water - especially as I don't own tongs for picking up hot jars as yet.
To steralise the jars put them into an oven at 120C after cleaning and leave them there until ready to use. Take out only one jar at a time when ready. This also has the benefit of heating the jars so that you can put hot food/jam into them.
It was much easier than I was originally thinking which makes me happy!!!