They will try their best to cut your dog's nails. If he is too aggressive they may charge you an extra fee, and if they are truly unable to handle your pet they may ask to sedate him so as to protect themselves and your pet.
RJ is right. A dog should be trained to not be aggressive. If he's a recent rescue, understandable some. Use a halter and leash, put a muzzle on the dog and try taking them. They protect all of the animals and the people, so if that dog is aggressive as it shouldn't be, they will have you stand outside which happens. They have another entrance so you can go inside the front and ask first. If you can, go in on a Friday earlier morning as a walk in, they normally open around 830, and it's normally far less people. Best place ever hands down.
Thanks! Your answer is awaiting moderation.