What is this at bottom of skirting boards?

[oldcottage20]

Hi. Does anyone know what this is at the bottom of my skirting boards? I hoover it up and it comes back within days. Thanks.

Looks like the wood is crumbling away from the inside. I've never actually seen it so this is a stab in the dark, but maybe it's caused by woodworm?

That's weird. Looks like grit. Is this upstairs or downstairs? Are you on timber joists?
Looks almost like somethings tunnelling up from underneath 😱

Could be insects.

I used to have ants in my conservatory (now all dead due to the great war on ants).

In the gap between the skirting board and floor there would be little piles of dirt that the ants would excavate to make their home.

So could be ants, woodworm, big spider making itself a cave. Maybe even a queen wasp gone in the gap and chewing out a space for winter.

TIL spiders make themselves caves. How cute, @GasPanic.

We had carpenter ants and they eat wood and leave deposits like those. First thing is to stop them. If it is carpenter ants they might have damaged the wood..my husband had to cut out some wood and replace it. Think I used bicarbonate of soda to get rid of the ants.. Google it. If you have them and the powder works, you will stop seeing the deposits.