[pcm81]

So, i have a 1 micron vacuum funnel filter. Similar to this: https://www.amazon.com/StonyLab-Borosilicate-Filtering-Diameter-Tubulation/dp/B0785Y8KDD/ref=sr_1_4?crid=QLG0LH71GV38&keywords=vacuum+funnel+filter&qid=1676220140&sprefix=vacuum+funnel+filter%2Caps%2C109&sr=8-4

The filter is now dirty... brown in color. I do use filter paper on top of it to minimize its contamination.
I tried cleaning it before using lye and acid (separately) to a marginal success. I am thinking lye may be etching actual glass as much as cleaning the filter.
So this got me thinking... What process can be used to clean out glassware like a filter when contaminants are unknown? I used it to filter solutions prior to recrystalization, so the contaminants are whatever were the impurities in the chemicals.

Is there a general set of liquids i can drive through the filter to dissolve all types of impurities?
Acids, bases, Oxidizers, Reducers, other? Best choice of solvents and recommended order?  Or is something like pirana solution is basically a 1 step process for this?

Thanks

[Babcock_Hall]

I don't have a general answer to your question.  However, I usually use Celite (diatomaceous) earth on top of the sintered glass funnels that I have, so that it does most of the filtration.