How to adjust OHLC chart values so none are negative

[rlewkov]

Hello,
Let's say I have an indicator, whose source I don't have, that operates on daily chart data but provides errant results if any of the chart OHLC values are negative which they could be if the chart is a spread.
Can anyone suggest a method to adjust a chart's OHLC values so that none are negative thereby allowing the indicator to behave correctly?

Thanks