WIP sanitize with surrounding numbers

@ggrossman 

This is a brute force strategy. Seems to be working. thoughts?
but but but performance! It's like 5 times faster

```
>> Benchmark.realtime { 10_000.times { (size < 19 && size || 19) } }
=> 0.00093
>> Benchmark.realtime { 10_000.times { [size, 19].max } }
=> 0.004552
```