[matt10379]

 I have been called by a customer today about marks on the window sills of his wooden windows. There are small circular marks on the window sills in certain places but not on every window. I have been cleaning their windows for 5 /6 years and the marks have appeared since April. The windows were put in around 2012.  I am almost certain that my wfp has not caused these marks but does anybody have any idea what they are from the pictures i've posted?

Thanks in advance
Matt

[Cookie]

Could it be where paint is flaking off a knot in the wood underneath?

[p1w1]

Could it be where paint is flaking off a knot in the wood underneath?

i reckon your right

[matt10379]

That was what i thought so you have pretty much confirmed what i was thinking.
Thanks

[Shrek]

Could it be where paint is flaking off a knot in the wood underneath?

I was gonna say that too - it’s got to be knots