So the head is off? If so remove the valve and clean up with a metal polish. Don't use abrasive wet and dry. The problem with the rust is that it may be also on the face of the valve a seat. If it is then do a quick regrind using fine valve paste..

Use a green Scotchbrite, and look for any pitting on the valve/seat.

where those circles are is the top of the valve seat not where the valve makes contact with the seat ,that mtr has only sat for a few mths now
spray it all with crc keep in a clean dry place till you want to use them ,if your going to do build port/polish the heads will need a service after any ways
mtrs sit around for years and have no problams if lubed turned over every now or than and depending what fuel you where using before you stop using that mtr
you do get that brown stain like rust on the valve/guides

If the heads are off then take out the valves and get some valve grinding compound, and a tool and regrind the valves back into their seats. No need to use purple polish or anything. The compound is available at Super-cheap along with the tool to hold the valves. A 5 min job to clean the faces of both the valves and seats up..

Hey Rod, It should only be very light surface rust and will most likely clean off with a rag and WD-40. BUT if you pull the valves and are unsure, take a pic of the removed valve and the seat showing the rust and we will comment further. A valve lapping tool is like a mini plunger that sucks to the chamber side of the valve, and when you apply a small amount of paste to the valve seat to be lapped, With valve inserted into guide you then rub the handle between your palms like a stick trying to start a fire. It mates the to surfaces together for correct sealing and seating. It may not need this like i said, hopefully will clean up with wd and a rag. See how you go.

https://www.youtube.com/watch?v=7GEmuQa3dPY

 

Explians everything.  And you don't need to be a tech minded person to carry out this task

Lol....I finish my valves with toothpaste too....

Toothpaste is good shit. I polish my watch face with it when it gets a bit scratchy, and also use it to give the car windscreen a really good clean. Works wonders..........

Just be careful not to damage the valve seals

Pretty suprising if the heads had been to Hallams already, surely they would of at least looked in the ports. HMMMMMM!!!!

Hallams do good heads I'm told.