The contamination was fixed enough that it was easy for the riggers to get up close & personal with the slings as they came out of the 55 gallon drum...as long as the slings were pulled at a slight angle by the crane, so the drips all fell on one side and the riggers stayed out from under the dripping portion.
The biggest problem was that we were at a PWR and the borated water pulled milky-looking residue out of the slings. I don't know if a pool with un-borated water would have this problem. I don't remember off the top of my head what they decided the chemical make-up of the residue was (talc?), but it didn't keep them from using the slings. I will try to track down some of the old group & see if anyone remembers how we decided there wasn't an issue with putting them in the pool like that.
I do remember that there were concerns about the life of the slings in borated water & someone (the manufacturer? our engineers?) blessed them off. I will try to get more details on that aspect, also.
Okay, I talked to the few ISFSI guys I still keep in touch with & they didn't remember much more than me...it's been 10 years...

Here's what I did get:
1. Rinse the slings each time before they go back in the pool...this will:
a. Minimize the milky residue.
b. Cause the slings to wick up as much clean water as possible, thus minimizing the amount of contamination they soak up.
2. We might have written off the chemical concern based on it being a D&D job. If you are still operating & have to consider primary water chemistry, you might not be able to use kevlar...but no one remembered for sure what the residue was...although talc was mentioned.
3. Everyone drew a blank on how we decided there wasn't a kevlar/boron life-of-sling issue.
I'll chase a couple more leads, but...sorry...