'Restoration' is a tricky term, and doesn't really have any 'appropriate' use for ancient coins. A 'restored' coin sort of implies smoothing or tooling (i.e. recutting the details of the coin) - a practice that is usually considered to ruin the authenticity of the coin/
For ancient coins, 'restoration' is better substituted for 'conservation' - usually nothing more than removing surface dirt, which can be achieved by a long soaking in olive oil - usually measured in months, sometimes in years. These coins appear to have already been cleaned - in fact, a little over cleaned, as some metal is showing through. I would leave them as is - the exposed metal will darken over time and I doubt much more would be revealed, even with professional cleaning.
They aren't too shabby either, I think there is a lot to see on these:
#1 is Constantius II, the reverse reads FEL TEMP REPARATIO (Happy times have been returned) and shows a roman soldier spearing a barbarian falling from a horse (this is the 'Fallen Horseman' reverse type).
#2 is Constantine the Great, the reverse reads DN CONSTANTINI MAX AVG / VOT XX.
#3 is Valens, the reverse reads SECVRITAS REIPVBLICAE (Security of the Republic - but earlier in the century, this same reverse would have read more along the lines of 'carefree republic' - how times changed in the late empire...). Star over F / M was issued from Siscia.
#4 is Constantius II again, but I can't make out what is written inside the wreath (VOT / ? / MVLT... / ?)
#5 I can't make out, but it looks like something might be identifiable from a better picture.
#6 is another Constantius II fallen horseman. Looks like the mint mark (bottom of the reverse) might still be there too, if you can get a picture.