Sweets 7.62 is a great bore cleaner but it does have a bit of a smell. If you are receiving hard core fouled bores than you had best clean it yourself and than hand the Cadet a rifle that he or she can maintain.
By far the strongest and most controversial solvent is a 50/50 mix of hydrogen peroxide and vinegar. It will clean anything out of your bore. I use this mix exclusively on every bore of every rifle that I own and I have never had a moments trouble with it but beware, it a powerful oxidizer and it will attack anything that is not blued or painted.