I have been trying for hours and also searching for assistance on using the destring, ignore command since I have a varlist "ph_pta" that contains pH values ( should be formatted: "7.40" as an example"

Some of the observations have "<" or random other characters that I have tried directly typing the command in the line or even using the Data- convert string var to numeric var menu. I have 6 or 7 characters that I've manually found that need to be removed so that I can then proceed with destring and convert this varlist to numbers.
I've tried ignore("<" "-" "`"), which is how I've seen it is supposed to be formatted?
I've also tried with commas in between each of those.
The error I most often get is "too few quotes. It adds its own quotes & `' each time also, when I use the menu.

Please assist. I can give you more info too if needed.