well im about to do my engine swap but befor i go about doing this im wanting to clean my car (kinda)

last time i ran my car was in some really wet/sandy conditions down by the river. i was about to pull my glow plug when i decided it was a bit too nasty down inside the head... i dont want sand inside the block so what would be the best way to clean this out!

its kinda caked in so i took a can of air and tried to shoot it out but it didnt work too well

any suggestions!