They had a lower credit score. 

Let him know that if he doesn't come up with the deposit, and co-signer within 5 days you will file for eviction which will ruin his credit rating and ability to rent in the future.

@Maugno Mora have you thought about doing a Home Equity Line of Credit instead of selling or refinancing?  

If you are tight on cash flow, it is recommended not using reserve, but these days we have credit card that can cover the unexpected repairs, so not using your reserve for other deals might be bad financial decisions. 

I assume you would also recommend meeting with local banks and credit unions?

I remember a BP Podcast where the guest was speaking about a single commercial loan that wrapped a few properties and also had an equity line of credit attached that he could draw from.

I offered to help remove trash recycles compresser cardboard remove left over items from refrigerator and pantry.She never returned so I hired a friend w truck to take to town dump.I drive a suburu and didn't have space to haul garbage.I had to repair split on inside of front door punch hole in hallway that was taped over.1 cat turned into4 so I had to wipe white silkey hair out of floor ventsalso vacume litter clean out garage refrigrater wipe and remove leftover stuff in drawers.Me rental had to set off 5 bugs bombs before she could sleep in home.I was quoted$800 for assurant pest controll to travel to sheltercove.I live in a rural area by the coast.I am ordering natural pest controll products and will hire a friend to spray.Northern calif doesn't have roaches so last tenants brought in.Last tenants are threatening me w lawyer if I don't return full deposit1800.I silent 15 hours doing repairs due to damage.I also had new tenants internet installer remove part from dish to mail to last tenants.Previous female tenant said they had that set up but new tenants have dogs in back yard.Also No one contacted me from previous renters about scheduling part removal.So as a courtesy I will mail back to Vegas and keep receipt.I am getting threatening texts demanding full deposit.Also they say I owe back rent from Sept 10 to Oct 1 but they didn't return to get what was left for me to deal with.I am cleaning vacation rentals and am still getting a list of damages.I'm ordering natural German cockroachkit online will arrive 2 days shipping cost 29 plus products gonna run another100.

If they are former tenants, then I want their credit scores and proof of previous payment or they are going to be leaving.

I found someone who just graduated from college and said that she doesn't have the best credit because of some credit card mistakes she made in college.

I'm trying to determine what a bank or credit union will give me.