First question, do they need:
1. Direct transcription, no cleanup/repair
2. Some noise reduction
3. Major repair
In the first case, there is a lot of software to buy or free
The noise profile/reduce function in Exact Audio Copy can target constant noise - eg. tape hiss, record surface noise - and probably hum as well. EAC cannot do anything for record scratches - compared to digitalt pops fron a CD misread, they just aren't sharp enought for it to find - similarly, no auto track splitting (cuesheet) as the gaps are not quiet enough - though you can manually place the track points.