Picture posting is enabled for all :)
Have to say in the last 30 years I have never seen grubs crawling into a pot through the drainage hole.
I'm with the drowning method.As a suggestion I would add a drop of Jeyes fluid into the water and this would permeate around the root system thus make the roots smell less attractive and palatable to the grubs.I use a similar method as this when I plant my brassicas to deter root fly which is similar situation i e fly/grubs.Word of warning don't over do the jeyes fluid on indoor pants or else you might deterred too.
what's the dilution for root fly tg think i might give it a try this year i'm plagued by them
Like the drowning idea, Vinlander.How smelly is using the microwave? Guess that kills all the 'good guys' as well.