These are configuration files. It's probably best to leave them alone if don't know what there are for. At least back them up before you delete them, then you can replace them when things stop working.
they are files that avg anti virus download when updating & run tests.
A friend has quite a few downloaded & says that it also saves these files when a virus test is run so wondered if they were safe to delete as there will be stacks of them at the rate he runs virus tests on floppy etc
I don't use avg so I can't comment on what the files may be for. If these files are large and your short of space, you could try renaming the older ones and see if anything stops working. If all is ok you can then delete them.
In the past I have had to restore my complete system after getting carried away with the house keeping. Modern hard drives are so vast it is safer to leave things that your not sure of alone.