/diy/ - Do It Yourself

I have a set of four hardwood outdoor chairs that have been exposed to the elements for roughly a year now.
I took them inside to dry out and want to refinish them. They used to get treated with oils every year back when they werent out in the rain. I’m thinking of just varnishing them this time around.

Problem is, the rain has made the ‘erosion’ very uneven, and I’m looking for a way to get rid of that without explicitly sanding. Are there chemicals I could apply that would do the job even better? Or is using a high powered pressure washer something I should consider?