Everything gets charged, benefit from all rewards, I pay my monthly statement from my HELOC every month in full and carry no balance over (I get to write off all the interest paid on my HELOC in the first position), as interest on the HELOC is calculated differently from a traditional mortgage.

If you're charging premium rent with a nice rehab I'd replace with same features. 

What is REI Blackbook charging for what you want?

For example last month i was charged $250 to put salt on the steps and sidewalks. 

Find out how they charge you interest, is it on the total loan amount from funding, or do they charge you based on funds you've used (some lenders do not charge you on the whole rehab budget until you use it)?

Take the emotions out of it If property is in good condition.

I recently closed on a duplex in New Jersey and will need to start purchasing materials for the rehab and wanted to see if I could charge those expenses on my business credit card.

Guilty as charged. 

Meaning write the description, take the photos, figure out how much you plan to charge.

If the house was rented to them with a good lawn, then I would charge them for the grass replacement.