brow tips. cut them??

my plants are 5 weeks old. all the leaves look great except for the very bottom ones. the ones a plant grows first. they have tiny crackly brow tips and have been this way for some time without any effect on the surrounding leaves. the tips seem to get a little more brown with each passing day and the plants themselves look overall very healthy.. what should i do? just leave them alone? or do i cut off the bad tips? ill take any advice. thanks. and the very bottom leaves are yellow, they recently had a nute burn so i flushed them..

Now im not a O.G on growing but i read somewhere on here to leave them the plant knows when to let them go or not if there still hanging on the plant must be utilizing them for something. Dont take my word for it but its just something I read on here while researching on my own grow btw plants look good bro keep up the good work!!

those are feeder leaves, when they turn yellow it means the plant is lacking nitrogen. feed them something with a medium/high N value.