Marks on washing - any clue as to what could be causing this?

[PunishmentRoundupWithJoon]

Can anyone offer any insights as to what these marks might be on this t shirt? They seem to be happening a lot to my partners clothes and we're both clueless. We live separately and this doesn't happen with my machine but his clothes are getting this a lot.

All the marks are like this - light in colour, stripey. It looks almost like a paint mark, but it definitely isn't. If brushed thoroughly they will fade slightly but not disappear. This only happens with his machine.

They're not there before being washed.

Any insight/opinion gratefully received!

The photos may take a while to upload due to mumsnet checking them first for dodgy images.

More pics

I sometimes get similar - not sure what they are but I think they tend to happen when machine very full.

Do you use washing powder as opposed to liquid?

Do they disappear with further washing in your machine? If so I suspect his machine is getting gummed up and not rinsing properly and these are dried washing pod marks.

Try washing some old towels at 90 degrees but without adding any washing pods.

Then wipe around all bits of the door and seal to check no sludgy stuff there.

Then try washing as normal but using powder rather than pods and without any fabric conditioner

Using washing powder on short/cool wash? It needs a long wash to dissolve.

Too much in the machine, too much washing powder, machine is dirty or the door is dirty.
Clean the machine put less in with correct amount of powder

Do they come out on the next wash? They might be powder residue from either too much powder or the washing machine being too full and not rinsing properly. I'd start with an empty load wash to clean the machine first.

Check that the inside of the door seal is clean.

@hyggetyggedotorg - he uses non bio washing powder. I use the same but it never happens in my machine.

@Busylikeabee - Yes, they come out when I wash them in my machine. I will pass on all this information to him!

@Twoshoesnewshoes - I think he does often use a 30 degree wash, so suppose it could be that?

I use an eco powder. It specifically says to wash at 40 degrees or above. Check what temp he’s using.

Short wash cycle, 30 degree temperature, using powder, all add to washing powder residue.

I did wonder if it was the temperature - I guess combined with the short cycle, that could be the culprit.