We mandate that our temp service informs all potential candidates of our General Rules and GMPS which includes the piercings (other than tongue rings and anything I cannot see ), fake/painted nails, and eye-lashes. All potential temps have to sign off on this and I consider it to be part of the prerequisite training prior to working which is required by SQF. I put that training on the temp agencies by training them as contract service providers. Just like we have specs to conform to as do they. Our product is food and theirs is temporary employees. Theirs should clearly state: "no pirecings etc. etc.". They do their best to ensure that none of the aforementioned foreign objects make it into the building but you will encounter people who think they are slick. In this case we will place them on a job that does not come into contact with food or ingredients i.e. warehouse work. That can't always be the case because we are still on the smaller scale of companies so if there is no position like that available they are given the ultimatum "remove or leave", which can hurt you on a desperate day but you can't make exceptions to rules for a single individual. It sounds harsh but if potential temps know this in advance they can only be mad at themselves for wasting their time.
See 2.3.3 Contract Service Providers and be sure to put temp agencies on your register with GMPS, General Rules and anything else you deem necessary. Train them (temp agencies), rinse and repeat. Have them run a perpetual log of sign-offs for prerequisite training and have them supply that list to you. All that being said, we still retrain on all of that material when it appears there may be some potential of hiring. The turn over rate is too high to ever keep up with doing all of it ourselves.
We took the band-aid approach for some time (pre-SQF) but it is just a hassle. With SQF those metal detectable band-aids will start to add up....